ACS Spring 2008 meeting - Femtosecond presentations for attention of Del Mar Photonics team members attending ACS meeting
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Trestles LH Ti:Sapphire
laser Trestles LH is a new series of high quality femtosecond Ti:Sapphire lasers for applications in scientific research, biological imaging, life sciences and precision material processing. Trestles LH includes integrated sealed, turn-key, cost-effective, diode-pumped solid-state (DPSS). Trestles LH lasers offer the most attractive pricing on the market combined with excellent performance and reliability. DPSS LH is a state-of-the-art laser designed for today’s applications. It combines superb performance and tremendous value for today’s market and has numerous advantages over all other DPSS lasers suitable for Ti:Sapphire pumping. Trestles LH can be customized to fit customer requirements and budget. Reserve a
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DPSS DMPLH lasers |
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New laser spectrometer
T&D-scan for research that
demands high resolution and high spectral
density in UV-VIS-NIR spectral domains - now available with
new pump option! The T&D-scan includes a CW ultra-wide-tunable narrow-line laser, high-precision wavelength meter, an electronic control unit driven through USB interface as well as a software package. Novel advanced design of the fundamental laser component implements efficient intra-cavity frequency doubling as well as provides a state-of-the-art combined ultra-wide-tunable Ti:Sapphire & Dye laser capable of covering together a super-broad spectral range between 275 and 1100 nm. Wavelength selection components as well as the position of the non-linear crystal are precisely tuned by a closed-loop control system, which incorporates highly accurate wavelength meter. Reserve a
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Ti:Sapphire laser from a kit |
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AOTF Infrared Spectrometer |
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Open Microchannel Plate Detector
MCP-MA25/2 -
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Hummingbird EMCCD camera The digital Hummingbird EMCCD camera combines high sensitivity, speed and high resolution. It uses Texas Instruments' 1MegaPixel Frame Transfer Impactron device which provides QE up to 65%. Hummingbird comes with a standard CameraLink output. It is the smallest and most rugged 1MP EMCCD camera in the world. It is ideally suited for any low imaging application such as hyperspectral imaging, X-ray imaging, Astronomy and low light surveillance. It is small, lightweight, low power and is therefore the ideal camera for OEM and integrators. buy online |
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Hatteras-D
femtosecond transient absorption data acquisition system Future nanostructures and biological nanosystems will take advantage not only of the small dimensions of the objects but of the specific way of interaction between nano-objects. The interactions of building blocks within these nanosystems will be studied and optimized on the femtosecond time scale - says Sergey Egorov, President and CEO of Del Mar Photonics, Inc. Thus we put a lot of our efforts and resources into the development of new Ultrafast Dynamics Tools such as our Femtosecond Transient Absorption Measurements system Hatteras. Whether you want to create a new photovoltaic system that will efficiently convert photon energy in charge separation, or build a molecular complex that will dump photon energy into local heat to kill cancer cells, or create a new fluorescent probe for FRET microscopy, understanding of internal dynamics on femtosecond time scale is utterly important and requires advanced measurement techniques. Reserve a
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training workshop in San Diego, California. |
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Beacon Femtosecond Optically Gated Fluorescence Kinetic Measurement System
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request a quote -
pdf Reserve a
spot in our Ultrafast Dynamics Tools
training workshop in San Diego, California. |
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Terahertz systems, set ups and components New band pass and long pass THz optical filters based on porous silicon and metal mesh technologies. Band pass filters with center wavelengths from 30 THz into GHz range and transmissions up to 80% or better. Standard designs with clear aperture diameters from 12.5 to 37.5 mm. Long pass filters with standard rejection edge wavelengths from 60 THz into GHz range. Maximum transmission up to 80% or better, standard designs at 19.0 and 25.4 mm diameters. Excellent thermal (from cryogenic to 600 K) and mechanical properties THz products: THz Spectrometer kit with Antenna THz transmission setup THz time domain spectrometer Pacifica fs1060pca THz time domain spectrometer Pacifica fs780pca THz detectors: Golay cell and LiTaO3 piroelectric detectors PCA - Photoconductive Antenna as THz photomixer Pacifica THz Time Domain Spectrometer - Trestles Pacifica Holographic Fourier Transform Spectrometer for THz Region Wedge TiSapphire Multipass Amplifier System - THz pulses generation Terahertz Spectroscopic Radar Mobile System for Detection of Concealed Explosives Band pass filters with center wavelengths from 30 THz into GHz range Long pass filters with standard rejection edge wavelengths from 60 THz into GHz range Generation of THz radiation using lithium niobate Terahertz crystals (THz): ZnTe, GaP, LiNbO3 - Wedge ZnTe |
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iPCA - interdigital Photoconductive Antenna for terahertz waves Large area broadband antenna with lens array and high emitter conversion efficiency iPCA with LT-GaAs absorber, microlens array for laser excitation wavelengths l £ 850 nm, adjusted hyperhemispherical silicon lens with a high power conversion efficiency of 0.2 mW THz power / W optical power. The iPCA can be used also as large area THz detector. The two types iPCAp and iPCAs have the same active interdigital antenna area but different contact pad directions with respect to the electrical THz field. Interdigital Photoconductive Antenna for terahertz waves generation using femtosecond Ti:Sapphire laser THz books |
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1. Femtosecond dynamic-absorption
studies of intermolecular vibrational coherence in bacteriochlorophyll and Zn–porphyrin
charge-transfer dynamics Warren F. Beck, beck@chemistry.msu.edu, Kevin L.
Dillman, Sanela Lampa-Pastirk, and Katherine R. Shelly. Department of Chemistry,
Michigan State University ...
2. Pump-DFWM-spectroscopy on β-carotene with shaped femtosecond pulses
Jurgen Hauer, Tiago Buckup, and Marcus Motzkus, motzkus@staff.uni-marburg.de.
Fachbereich Chemie, Philipps-Universitat Marburg, Hans-Meerwein-Strasse, 35037
Marburg, Germany Coherent control aims at influencing photochemical ...
3. Femtosecond and picosecond X-ray spectroscopy in chemical dynamics research
Christian Bressler, christian.bressler@epfl.ch, Laboratoire de Spectroscopie
Ultrarapide, Ecole Polytechnique Federale de Lausanne, ISIC-BSP, CH-1015
Lausanne, Switzerland We will present our recent results on the ...
4. Controlling the ablation of materials with pairs of femtosecond laser pulses
Robert J Gordon, rjgordon@uic.edu, Yongtao Cheng, Zhan Hu, Yaoming Liu, Ting Lu,
Sima Singha, and Tana E. Witt. Department of Chemistry, University of Illinois
at Chicago, 845 W. Taylor Street, Chicago, IL 60607 We ...
5. Photoinduced and dark bimolecular reactions in aqueous solutions of ruthenium
(II)-tris-(2,2'-bipyridine) upon high intensity femtosecond laser excitation
Alexander N. Tarnovsky, atarnov@bgsu.edu, Department of Chemistry & Center for
Photochemical Sciences, Bowling Green State University ...
6. Ultrafast dynamics in single-walled carbon nanotubes
... , (2) Department of Chemistry, University of North Carolina at Chapel Hill,
Caudill and Kenan Laboratories, Chapel Hill, NC 27599-3290 We have used
femtosecond transient absorption spectroscopy to examine the excited state
dynamics of single-walled carbon nanotube (SWNT) bundles embedded in polymer
matrices ...
7. Ultrafast magnetization dynamics in cobalt-doped iron oxide nanocrystals:
Effect of varying exchange interaction
... Station, TX 77842 The dynamics of photo-induced magnetization in chemically
synthesized Co-doped iron oxide nanocrystals were investigated by femtosecond
Faraday rotation measurements. Through the controlled doping of Co, nanocrystal
samples of varying Co content were prepared ranging from Fe 3O 4 to ...
8. Charge transfer induced proton-coupled electron transfer
... relaxation dynamics of a photoexcited hydrogen bound
4-hydroxy-4'-nitrobiphenyl and t-butylamine association complex have been
followed using both femtosecond and nanosecond transient absorption
spectroscopy. Upon photoexcitation, the biphenyl molecule undergoes an
intramolecular transition that transfers ...
9. Ultrafast coherent plasmon dynamics of individual metal nanostructures
... of individual, clean and adsorbate covered gold nanotips. We use
second-harmonic interferometric autocorrelation with sub-10 fs excitation. The
femtosecond temporal response of the plasmon polariton is found to be sensitive
with respect to the structural parameters of the tips in terms of apex radius
...
10. Photopolymerization of conductive metal nanoparticles
... using transmission electron microscopy (TEM) and scanning electron
microscopy (SEM). Electron transfer from ligand to metal was confirmed by
femtosecond transient absorption measurements. Ligand radical cation coupling
caused the linking of the metal nanoparticles. Photopolymerization of BTSH
functionalized ...
11. Ultrafast dynamics at the air/water interface investigated with
time-resolved electronic sum-frequency generation (TR-ESFG) spectroscopy
... of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama, Japan We
developed a new surface-selective time-resolved nonlinear spectroscopy,
femtosecond time-resolved electronic sum-frequency generation (TR-ESFG)
spectroscopy, to investigate ultrafast dynamics at liquid interfaces. Its
advantage ...
12. Ultrafast dynamics in the MLCT excited states of Ru(II) and Os(II)
coordination complexes
... complexes John M. Papanikolas, john_papanikolas@unc.edu, Department of
Chemistry, University of North Carolina, Chapel Hill, NC 27599 We have used
femtosecond transient absorption spectroscopy to address the fundamental
photophysics of metal-to-ligand charge-transfer (MLCT) excited states in both
symmetric ...
13. Advances in structural analyses of complex molecules
... sources like the LCLS at Stanford in the next few years. Such x-ray beams
will have much higher peak brightness (more than 10**10 and shorter
pulses(femtosecond rather than picosecond regime) than currently available.
Examples will be used to illustrate the potential of this new class of sources
for ...
14. First-principles approach to the anharmonic vibrational properties of
biomolecules
... Dynamics Laboratory, Institute of Chemistry, Chinese Academy of Sciences,
No. 2 1st North St. Zhongguancun, Haidian District, Beijing, 100080, China
Femtosecond two-dimensional infrared (2D IR) spectroscopy can be used to monitor
structures and dynamics of molecules in condensed phases by mapping out ...
15. Elucidation of mechanism following adaptive control of complex molecules in
solution
... . Department of Chemistry and Biochemistry, University of Colorado at
Boulder, Campus Box 215, Boulder, CO 80309 The significance of adaptive
femtosecond pulse shaping stems from the use of iterative learning which allows
for the control and study of electronically, structurally, and reactively
complex ...
16. Probing quasiparticle and electron correlations by coherent 2-D spectroscopy
... Li, and Rafal Oszwaldowski. Department of Chemistry, University of
California, Irvine, 1102 Natural Sciences II, Irvine, CA 92697-2025 Sequences of
femtosecond optical pulses are designed to generate signals that are induced by
correlations among elementary excitations. Applications to Frenkel excitons ...
17. Optimal control of photoproducts
... 117200, Gainesville, FL 32611-7200. We investigate the coherent control of
azobenzene's excited state population dynamics by adaptive pulse shaping.
Femtosecond excitation pulses perturb a molecule's excited state dynamics
modulating the process photochemical outcome. Combined with pulse shaping and
...
18. Ultrafast dynamics of electron transfer and solvation processes at ammonia
and water ice/metal interfaces
... ultrafast dynamics of interfacial electron transfer are studied for
ultrathin ice and ammonia layers adsorbed on Cu(111) and Ru(001) surfaces using
femtosecond time- and angle resolved two-photon-photoemission (2PPE)
spectroscopy. In this process, photo-injection of electrons from the metal into
the ...
19. Ultrafast 1- and 2-D infrared studies of complex chemical reactions
... .edu, James F. Cahoon, jfcaho@berkeley.edu, and Jacob P. Schlegel.
Department of Chemistry, University of California at Berkeley, Berkeley, CA
94720 Femtosecond infrared spectroscopy is a valuable experimental tool for
investigating the details of complex chemical reactions in ambient solution.
UV-pump ...
20. Watching the protein mambo: Spectroscopic probes of enzyme dynamics
... , samrat-dutta@uiowa.edu, and Amnon Kohen. Department of Chemistry,
University of Iowa, Iowa City, IA 52242 The structural dynamics of enzymes at
the femtosecond to picosecond time scale have been invoked to explain the
results of temperature-dependent kinetic-isotope-effect measurements for a
number ...
21. Nanoparticle induced light-harvesting membrane protein deformation (LH2)
revealed by ultrafast spectroscopic study of the excitonic states
... Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Hai
Dian Qu Zhong Guan Cun Nan San Jie 8 Hao, Beijing, 100080, China We used femto-second
time resolved transient absorbance difference spectroscopy to investigate the
membrane protein of a light-harvesting antenna complex (LH2 ...
22. Long-range proton transfer in aqueous acid-base reactions
... ,6-pyrenetrisulfonic acid (HPTS) and acetate in aqueous solution by probing
the vibrational resonances of HPTS, acetate and the hydrated proton with
femtosecond mid-infrared laser pulses. We find that PT in this model system
takes place in a distribution of hydrogen-bound reaction complexes that differ
...
23. Taking it to the limit: Ultrafast dynamics of heat transport over ultrasmall
distances
... and through molecules using an ultrafast heat bath. 1 The heat bath, a gold
substrate, is flash-heated up to 1000 K in approximately 1 ps with a femtosecond
laser pulse. A self-assembled monolayer, attached to the heat bath at one end by
a Au-S bond, heats as thermal energy surges into the molecules ...
24. Ultrafast infrared spectroscopy of dilute HOD in aqueous salt solutions
... . The direct measurement of the dynamics of water molecules in the first
solvation shells of Cl -, Br - and I - has been achieved recently by femtosecond
midinfrared nonlinear spectroscopy. The previous approach of the electronic
structure/molecular dynamics (ES/MD) method for calculating ultrafast
vibrational ...
25. Simulations of coherent exciton dynamics in multidimensional spectroscopy
... based on the nonlinear exciton equations is presented for simulating and
interpreting the response of chromophore aggregates to sequences of femtosecond
laser pulses. Applications are made to the Fenna-Matthews-Olson (FMO) light
harvesting complex. Some fundamental symmetries of multidimensional optical ...
26. Resolving the excited and ground state reaction coordinates in the green
fluorescence protein and mutants with dispersed pump-dump probe spectroscopy
... -state photodynamics of wild-type (wt), S65T/H148D and S65T/H148E mutants of
the Green Fluorescent Protein (GFP) system were characterized with femtosecond
time-resolved dispersed multi-channel pump-dump-probe measurements. Discrete
transient intermediates with specific spectral properties are identified ...
27. Hidden electronic excited state of enhanced green fluorescent protein (eGFP)
by new multiplex two-photon absorption spectroscopy
... absorption (TPA) spectroscopy, which enables us to measure precise TPA
spectra for a broad wavelength range, utilizing narrow-band and broad-band
femtosecond pulses with multichannel detection. We applied this technique to
study the electronic structure of enhanced green fluorescent protein (eGFP), ...
28. Infrared spectroscopy of tritiated water
... bond switching with correlation spectroscopy between the OD and OT
stretching vibrations in H2O. We report on the infrared absorption spectrum and
femtosecond infrared pump-probe spectroscopy of the OT stretching vibration of
HOT in H2O. We compare IR absorption line shape parameters between the three ...
29. Multiple exciton generation in semiconductor quantum dots and applications
to third generation solar photon conversion
... and hole relaxation, multiple exciton generation, cooling, charge transport,
and interfacial charge transfer of the photogenerated carriers with femtosecond
(fs) to ns time resolution. We have been studying these fundamental dynamics in
various bulk and nanoscale semiconductors (quantum dots (QDs), ...
30. New insights into electronic structures of semiconductor nanocrystals
through single-particle and ultrafast spectroscopies
... and ultrafast spectroscopic techniques. For example, we use single-nanocrystal
photoluminescence (PL) excitation spectroscopy in conjunction with femtosecond
time-resolved PL to study the structure of band-edge optical transitions and
mechanism for intraband relaxation. Further, we apply single-nanocrystal ...
31. Charge transfer excitons on a crystalline organic semiconductor surface
... of these transient species. Here, we report the observation of CT excitons
on the surface of a crystalline organic semiconductor, pentacene, from
femtosecond time-resolved two-photon photoemission spectroscopy. In this model
system, pentacene is the electron donor and vacuum is the “electron acceptor ...
32. Atomic solvation dynamics and the breakdown of linear response
... -solvated (Na +:e –) – a partially-atomic, solvent-supported tight-contact
pair (TCP) – created out of equilibrium through two well-defined pathways:
femtosecond photodetachment of Na –, and photoinduced electron
transfer/attachment to Na +. We find that the ultrafast time-resolved solvation
of nascent ...
33. Infrared pump-probe investigation of melanin vibrational relaxations
... properties of melanin samples prepared using a variety of techniques. The
melanin samples were characterized using FTIR and studied using femtosecond
infrared pump-probe spectroscopy. The pump-probe results allow for comparison of
the samples' efficiency at dissipating energy. These results will indicate ...
34. Photochemical investigations of diiron model complexes containing the
[Fe2O(O2CR)2]2+ core
... modulate dioxygen reactivity in these iron centers. Various optical
spectroroscopic methods (i.e., photoacoustic calorimetry, UV_Vis absorption and
femtosecond transient absorption spectroscopy) were employed to characterize the
electronic structure and excited state characteristics of these complexes ...
35. 1,2,3,4,5-Pentamethyl-cyclopentadiene dynamics probed by photoionization
... , the molecule has ample energy to form isomers. Our experiments show
conclusively, however, that no measurable structural changes take place on a
femtosecond or picosecond timescale. PHYS Poster Session - Optical Probes of
Dynamics in Complex Environments 7:30 PM-10:00 PM, Wednesday, April 9 ...
36. Static and time resolved vibrational sum frequency spectroscopy studies of
membrane bound water
... OD region at the membrane/water interface, using a variety of lipids and
trace HOD in H 2O, and the latter by application of the newly developed
femtosecond time resolved SFG to the same model membrane systems. Our results
suggest that water chemical heterogeneity differs between lipids in a chemically
...
37. Investigating semiconductor-photosensitizers using N3 dye analogs
... and electrochemistry, will be reported. Initial studies concerning electron
transfer dynamics of these dyes adsorbed onto TiO2 films using femtosecond
infrared spectroscopy will also be described. These studies will examine the
effects of adding alkyl bridges of increasing length on electron transfer ...
38. Electron transfer dynamics at the ZnO (10-10) surface
... in electron transfer across this surface and in electron transport in
devices featuring ZnO photoanodes. Additionally, we observe ultrafast sub-20
femtosecond cooling of hot electrons within the ZnO conduction band, suggesting
that hot carrier transport may not be feasible in this material. Interfacial ...
39. Effect of morphology in KNb6O17 nanosheets and nanoscrolls on photocatalytic
H2 evolution from water
... /h (175 mg of catalyst). Similarities and differences in the two catalysts
are discussed using data from TEM, HRTEM, UV/vis, fluorescence, IR, and
femtosecond absorption spectroscopy. 2nd Symposium on Hydrogen from Renewable
Sources and Refinery Applications 1:00 PM-5:00 PM, Sunday, April 6, 2008 ...
==============
1. 100%PHYS 352 - Ultrafast dynamics of intramolecular electron transfer in
2,7-dicyanospirobifluorene: Transient absorption anisotropy study
PHYS 352 Ultrafast dynamics of intramolecular electron transfer in
2,7-dicyanospirobifluorene: Transient absorption anisotropy study Artem
Khvorostov, artemkh@andromeda.rutgers.edu and Piotr Piotrowiak, piotr@andromeda.rutgers.edu.
Department of Chemistry, Rutgers, The State University of New Jersey ...
2. 99%PHYS 161 - Molecular structural dynamics studied by ultrafast optical and
X-ray transient absorption spectroscopy
PHYS 161 Molecular structural dynamics studied by ultrafast optical and X-ray
transient absorption spectroscopy Lin X. Chen, lchen@anl.gov 1, Xiaoyi Zhang 2,
Erik C. Wasinger, wasinger@anl.gov 3, Di-Jia Liu, liud@cmt.anl.gov 4, Klaus
Attenkofer 5, and Guy Jennings 5. (1) Chemistry, Argonne National ...
3. 99%PHYS 266 - Coherent, nonlinear, and ultrafast nanoplasmonics
PHYS 266 Coherent, nonlinear, and ultrafast nanoplasmonics Mark I. Stockman,
mstockman@gsu.edu, Department of Physics and Astronomy, Georgia State
University, Atlanta, FL 30303 This talk introduces and reviews new ideas and
recent progress in coherent, nonlinear and ultrafast nanoplasmonics. It includes
...
4. 98%PHYS 253 - Ultrafast 2-D vibrational spectroscopy of molecular monolayers
PHYS 253 Ultrafast 2-D vibrational spectroscopy of molecular monolayers Jens
Bredenbeck, bredenbeck@biophysik.org, Department of Physics, Johann Wolfgang
Goethe-University, Max von Laue Strasse 1, 60438 Frankfurt/Main, Germany,
Avishek Ghosh, ghosh@amolf.nl, Department of Femtophysics, FOM Institute ...
5. 98%COMP 41 - Ultrafast transformation of graphite to diamond: An ab initio
study of graphite under shock compression
COMP 41 Ultrafast transformation of graphite to diamond: An ab initio study of
graphite under shock compression Nir Goldman, goldman14@llnl.gov 1, Christopher
J. Mundy, chris.mundy@pnl.gov 2, Evan J. Reed 1, I Feng W. Kuo, kuo2@llnl.gov 1,
Laurence E. Fried, fried1@llnl.gov 3, and Alessandro Curioni ...
6. 98%PHYS 337 - Synthesis and ultrafast chelation dynamics of novel molecular
photoswitches
PHYS 337 Synthesis and ultrafast chelation dynamics of novel molecular
photoswitches Tung T. To, tung.to@nist.gov and Edwin J. Heilweil, edwin.heilweil@nist.gov.
Physics Laboratory, Optical Technology Division, National Institute of Standards
and Technology, 100 Bureau Drive Stop 8443, Gaithersburg ...
7. 98%PHYS 56 - Ultrafast optical studies of electronic relaxation across the
interface in CdS/CdSe/CdS quantum-dot quantum-well heterostructures
PHYS 56 Ultrafast optical studies of electronic relaxation across the interface
in CdS/CdSe/CdS quantum-dot quantum-well heterostructures Wei Qian 1, Alexander
W. Schill 2, Christopher Gaddis, chris.gaddis@gmail.com 1, and Mostafa A. El-Sayed,
mostafa.el-sayed@chemistry.gatech.edu 1. (1) Laser Dynamics ...
8. 98%PHYS 213 - Ultrafast response of semiconductor nanocrystals to high-photon
energy absorption: Multiexcitons from a single photon
PHYS 213 Ultrafast response of semiconductor nanocrystals to high-photon energy
absorption: Multiexcitons from a single photon Richard D. Schaller, rdsx@lanl.gov
1, Milan Sykora, sykoram@lanl.gov 2, Jeffrey M. Pietryga, pietryga@lanl.gov 1,
and Victor I. Klimov 1. (1) Chemistry Division, Los Alamos ...
9. 98%PHYS 165 - Ultrafast vibrational dynamics of asymmetric hydrogen-bonded
dimers
PHYS 165 Ultrafast vibrational dynamics of asymmetric hydrogen-bonded dimers
Poul B. Petersen, poul@mit.edu, Sean T Roberts, seanr@mit.edu, Matthew W. Kanan,
mkanan@mit.edu, Elizabeth R. Young, eyoung@mit.edu, Rebecca A. Nicodemus,
nicodemu@mit.edu, Krupa Ramasesha, Daniel G. Nocera, and Andrei Tokmakoff ...
10. 98%PHYS 351 - Ultrafast dynamics at the air/water interface investigated
with time-resolved electronic sum-frequency generation (TR-ESFG) spectroscopy
PHYS 351 Ultrafast dynamics at the air/water interface investigated with
time-resolved electronic sum-frequency generation (TR-ESFG) spectroscopy Kentaro
Sekiguchi, ksekiguchi@riken.jp, Shoichi Yamaguchi, shoichi@riken.jp, and Tahei
Tahara, tahei@riken.jp. Molecular Spectroscopy Laboratory, RIKEN ...
11. 98%PHYS 111 - Ultrafast X-ray spectroscopy and imaging of chemical and
physical processes
PHYS 111 Ultrafast X-ray spectroscopy and imaging of chemical and physical
processes Xiaodi Li, Brian Ahr, Christopher M. Laperle, and Christoph Rose-Petruck,
Christoph_Rose-Petruck@brown.edu. Department of Chemistry, Brown University, 324
Brook Str, Providence, RI 02912 Ultrafast high-intensity laser ...
12. 98%COLL 330 - Ultrafast dissociation of excitons in quantum dots
COLL 330 Ultrafast dissociation of excitons in quantum dots Abdelaziz Boulesbaa,
aboules@emory.edu, Jier Huang, jhuang8@emory.edu, Zhuangqun Huang, and Tianquan
Lian, tlian@emory.edu. Department of Chemistry, Emory University, 1515 Dickey
Drive, Atlanta, GA 30322 Multiple exciton generation, by which ...
13. 98%COLL 123 - Ultrafast dynamics of electron transfer and solvation
processes at ammonia and water ice/metal interfaces
COLL 123 Ultrafast dynamics of electron transfer and solvation processes at
ammonia and water ice/metal interfaces Martin Wolf, wolf@physik.fu-berlin.de,
Dept. of Physics, Freie Universitaet Berlin, Arnimallee 14, Berlin, 14195,
Germany The ultrafast dynamics of interfacial electron transfer are studied ...
14. 97%PHYS 304 - Ultrafast magnetization dynamics in colloidal magnetic
nanocrystals
PHYS 304 Ultrafast magnetization dynamics in colloidal magnetic nanocrystals
Chih-Hao Hsia, chhsia@mail.chem.tamu.edu, Tai-Yen Chen, tychen@mail.chem.tamu.edu,
and Dong Hee Son, dhson@mail.chem.tamu.edu. Department of Chemistry, Texas A&M
University, College Station, TX 77842 Ultrafast magnetization ...
15. 97%PHYS 329 - Applications of ultrafast 2-D infrared spectroscopy to studies
of the Fe-hydrogenase enzyme system
PHYS 329 Applications of ultrafast 2-D infrared spectroscopy to studies of the
Fe-hydrogenase enzyme system A. Ian Stewart 1, M Towrie 2, Ian P Clark 2,
Anthony W. Parker 2, Saad Ibrahim 3, Chris J Pickett 3, and Neil T Hunt, nhunt@phys.strath.ac.uk
1. (1) Department of Physics, University of Strathclyde ...
16. 97%PHYS 303 - Ultrafast dynamics in single-walled carbon nanotubes
PHYS 303 Ultrafast dynamics in single-walled carbon nanotubes David J. Styers-Barnett
1, Brian P. Mehl 1, Brittany C. Westlake, westlake@email.unc.edu 2, and John M.
Papanikolas, john_papanikolas@unc.edu 1. (1) Department of Chemistry, University
of North Carolina, Chapel Hill, NC 27599, (2) Department ...
17. 97%INOR 931 - Ultrafast exciton dynamics in OLED materials
INOR 931 Ultrafast exciton dynamics in OLED materials Pavel Anzenbacher Jr.,
pavel@bgsu.edu, Department of Chemistry and Center for Photochemical Sciences,
Bowling Green State University, 141 Overman Hall, Bowling Green, OH 43403
Achieving control over the dynamics of excited states is crucial for ...
18. 96%PHYS 620 - Ultrafast infrared spectroscopy of dilute HOD in aqueous salt
solutions
PHYS 620 Ultrafast infrared spectroscopy of dilute HOD in aqueous salt solutions
Yu-Shan Lin, lin5@wisc.edu, Department of Chemistry, University of Wisconsin -
Madison, 1101 University Ave, Madison, WI 53706-1322 and J. L. Skinner, skinner@bert.chem.wisc.edu,
Department of Chemistry, University of ...
19. 96%PHYS 342 - Ultrafast photophysics of conjugated polyelectrolytes
PHYS 342 Ultrafast photophysics of conjugated polyelectrolytes Gustavo M Moriena,
gustavom@chem.ufl.edu 1, Sevnur Komurlu, sevnur@ufl.edu 1, Xiaoyong Zhao, xyzhao@chem.ufl.edu
1, Seoung Ho Lee 1, Hui Jiang, huijiang@chem.ufl.edu 1, Kirk S Schanze, kschanze@chem.ufl.edu
2, and Valeria D. Kleiman, kleiman ...
20. 96%PHYS 340 - Ultrafast time-resolved measurements of a novel organic
multichromophore TNT sensing material
PHYS 340 Ultrafast time-resolved measurements of a novel organic
multichromophore TNT sensing material Aditya Narayanan, adityann@umich.edu,
Department of Macromolecular Science and Engineering, University of Michigan,
930 N.University Avenue, #4830, Ann Arbor, MI 48109 and T. Goodson III, tgoodson
...
21. 95%PHYS 341 - Ultrafast magnetization dynamics in cobalt-doped iron oxide
nanocrystals: Effect of varying exchange interaction
PHYS 341 Ultrafast magnetization dynamics in cobalt-doped iron oxide
nanocrystals: Effect of varying exchange interaction Chih-Hao Hsia, chhsia@mail.chem.tamu.edu,
Tai-Yen Chen, tychen@mail.chem.tamu.edu, and Dong Hee Son, dhson@mail.chem.tamu.edu.
Department of Chemistry, Texas A&M University ...
22. 95%PHYS 250 - Ultrafast 1- and 2-D infrared studies of complex chemical
reactions
PHYS 250 Ultrafast 1- and 2-D infrared studies of complex chemical reactions
Charles B. Harris, cbharris@berkeley.edu, Karma R. Sawyer, karma@berkeley.edu,
James F. Cahoon, jfcaho@berkeley.edu, and Jacob P. Schlegel. Department of
Chemistry, University of California at Berkeley, Berkeley, CA 94720 ...
23. 95%INOR 985 - Ultrafast dynamics in the MLCT excited states of Ru(II) and
Os(II) coordination complexes
INOR 985 Ultrafast dynamics in the MLCT excited states of Ru(II) and Os(II)
coordination complexes John M. Papanikolas, john_papanikolas@unc.edu, Department
of Chemistry, University of North Carolina, Chapel Hill, NC 27599 We have used
femtosecond transient absorption spectroscopy to address the fundamental ...
24. 95%PHYS 445 - Ultrafast coherent plasmon dynamics of individual metal
nanostructures
PHYS 445 Ultrafast coherent plasmon dynamics of individual metal nanostructures
Alexandria Kappus, alex63@u.washington.edu, C. C. Neacsu, neacsu@u.washington.edu,
and M. B. Raschke, raschke@chem.washington.edu. Department of Chemistry,
University of Washington, 36 Bagley Hall, Seattle, WA 98195 The ...
25. 95%PHYS 681 - Dynamics and control of ultrafast nonadiabatic processes
PHYS 681 Dynamics and control of ultrafast nonadiabatic processes Albert Stolow,
Albert.Stolow@nrc.ca, Steacie Institute for Molecular Sciences, National
Research Council of Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada
Time-Resolved Coincidence Imaging Spectroscopy makes use of 3D particle ...
26. 95%PHYS 301 - Taking it to the limit: Ultrafast dynamics of heat transport
over ultrasmall distances
PHYS 301 Taking it to the limit: Ultrafast dynamics of heat transport over
ultrasmall distances Jeffrey A. Carter, jcarter3@uiuc.edu, Zhaohui Wang, and
Dana D. Dlott. Department of Chemistry, University of Illinois at
Urbana-Champaign, Urbana, IL 61801 We have developed a new method for studying
the ...
27. 95%PHYS 345 - Aqueous hydroxide ion transport dynamics probed using
ultrafast vibrational echo experiments
PHYS 345 Aqueous hydroxide ion transport dynamics probed using ultrafast
vibrational echo experiments Sean T Roberts, seanr@mit.edu, Poul B. Petersen,
poul@mit.edu, Krupa Ramasesha, and Andrei Tokmakoff. Department of Chemistry,
Massachusetts Institute of Technology, 77 Massachusetts Ave., Room 6-030 ...
28. 95%PHYS 112 - Ultrafast X-ray scattering studies of structural dynamics
PHYS 112 Ultrafast X-ray scattering studies of structural dynamics Kelly J.
Gaffney, kgaffney@slac.stanford.edu, Stanford Linear Accelerator Center,
Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025 Measuring atomic
resolution images of materials with x-ray photons during chemical reactions ...
29. 95%COMP 197 - Temperature dependent structural dynamics of the Villin
Headpiece Helical Subdomain: An ultrafast folding protein
COMP 197 Temperature dependent structural dynamics of the Villin Headpiece
Helical Subdomain: An ultrafast folding protein Lauren Wickstrom, lwick442@yahoo.com,
Stony Brook University, Biochemistry and Structural Biology, Stony Brook, NY
11794, Scott H. Brewer, Chemistry Department, Franklin & ...
30. 94%COLL 333 - Ultrafast electron solvation and transfer dynamics at protic-solvent/TiO2
interfaces
COLL 333 Ultrafast electron solvation and transfer dynamics at protic-solvent/TiO2
interfaces Hrvoje Petek, Department of Physics and Astronomy, University of
Pittsburgh, Pittsburgh, PA 15260 We study the electron solvation and reverse
charge transfer dynamics of partially solvated “wet” electrons ...
31. 93%PHYS 318 - New insights into electronic structures of semiconductor
nanocrystals through single-particle and ultrafast spectroscopies
PHYS 318 New insights into electronic structures of semiconductor nanocrystals
through single-particle and ultrafast spectroscopies Victor I. Klimov, Chemistry
Division, Los Alamos National Laboratory, MS-J567, Los Alamos, NM 87545
Semiconductor nanocrystals are stable, spectrally tunable chromophores ...
32. 92%PHYS 25 - Nanoparticle induced light-harvesting membrane protein
deformation (LH2) revealed by ultrafast spectroscopic study of the excitonic
states
PHYS 25 Nanoparticle induced light-harvesting membrane protein deformation (LH2)
revealed by ultrafast spectroscopic study of the excitonic states Yu-Xiang Weng,
yxweng@aphy.iphy.ac.cn, Laboratory of Soft Matter Physics, Institute of Physics,
Chinese Academy of Sciences, Hai Dian Qu Zhong Guan Cun ...
33. 91%PHYS 685 - Multidimensional wave packet dynamics in ultrafast molecular
fragmentation
PHYS 685 Multidimensional wave packet dynamics in ultrafast molecular
fragmentation Thomas C Weinacht, tweinacht@sunysb.edu and Sarah R Nichols.
Department of Physics and Astrononmy, Stony Brook University, Stony Brook, NY
11794-3800 This talk will focus on the interpretation of pump-probe measurements
...
34. 90%PHYS 113 - Probing charge-transfer processes in solution with ultrafast
X-ray absorption spectroscopy
PHYS 113 Probing charge-transfer processes in solution with ultrafast X-ray
absorption spectroscopy Munira Khalil, mkhalil@chem.washington.edu, Department
of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700 This
talk will outline the use of time-resolved x-ray absorption spectroscopy ...
35. 13%PHYS 227 - Two-dimensional electronic spectroscopy of photosynthetic
complexes
PHYS 227 Award Address (Ahmed Zewail Award in Ultrafast Science and Technology,
sponsored by Ahmed Zewail Endowment Fund established by Newport Corporation).
Two-dimensional electronic spectroscopy of photosynthetic complexes Graham R
Fleming, GRFleming@lbl.gov 1, Elizabeth Read 2, Tessa Calhoun 2 ...
36. 11%INOR 932 - Structural dynamics of photoactive metal complexes in solar
energy conversion
... their structures with atomic resolution and sufficient time resolution is
crucial in correlating structures with molecular properties. Combining ultrafast
optical and x-ray transient absorption spectroscopy, the structural dynamics of
several important metal complexes can be obtained, including their ...
37. 11%PHYS 346 - Local interfacial electronic structure of thin pentacene films
on Si(111)
... -0041 Organic photovoltaic (OPV) devices offer a promising route to low-cost
solar energy harvesting. These systems have demonstrated heterogeneous ultrafast
charge transfer dynamics in part due to complex micro and nanoscale disorder at
semiconductor domain interfaces. We have investigated the effects ...
38. 11%COLL 329 - Watching excitations diffuse and charges recombine at
interfaces in organic photovoltaic materials
... separation, excitation transport, and charge recombination at the interfaces
of polymer blend organic photovoltaic materials are examined using ultrafast
visible pump – infrared probe spectroscopy. Native vibrational modes of both the
electron donating polymers and electron accepting fullerenes are ...
39. 11%PHYS 251 - Nonequilibrium dynamics studied with transient Fourier
transform 2-D IR spectroscopy
... 48109 The power of two-dimensional infrared (2DIR) spectroscopy to reveal
equilibrium vibrational coupling, loss of transition frequency memory and
ultrafast chemical exchange has been firmly established in recent years. A long
standing challenge of ultrafast spectroscopy is to study chemical reaction ...
40. 11%PHYS 331 - Charge transfer induced proton-coupled electron transfer
... , the biphenyl molecule undergoes an intramolecular transition that
transfers charge from the hydroxy end of the molecule to the nitro- end.
Ultrafast measurements show direct evidence that relaxation to ground state
(i.e. back electron transfer) is coupled to proton transfer from the hydroxyl
group ...
41. 11%PHYS 114 - Femtosecond and picosecond X-ray spectroscopy in chemical
dynamics research
... will present our recent results on the light induced structural dynamics of
molecules in solution using an optical probe/X-ray probe method based on
ultrafast X-ray absorption spectroscopy. This approach was applied to
photoexcited coordination chemistry compounds next to nascent atomic radicals in
...
42. 10%PHYS 374 - Electron transfer dynamics from organic dyes to semiconductor
nanocrystalline films
... organic dyes (xanthene, coumarin, and stylene derivatives) to different
semiconductors (TiO 2, SnO 2, In 2O 3, ZnO) were investigated using both
ultrafast IR and visible transient absorption spectroscopy. The IR injection
dynamics to the different semiconductors were directly correlated with visible
...
43. 10%PHYS 298 - Charge and energy transfer dynamics in nanoscale systems
... of the nanocrystal only. To examine this assumption we have prepared and
examined a series of nanocrystalline donor-acceptor systems that undergo
ultrafast photo-induced electron transfer. A particular attribute of systems
like nanocrystalline quantum dots is that the electronic levels can be modified
...
44. 10%PHYS 686 - Optical control in simple chemical systems
... chemical systems Roseanne J. Sension, rsension@umich.edu, FOCUS Center,
University of Michigan, 930 N. University, Ann Arbor, MI 48109 Advances in
ultrafast laser technology have led to the development of sophisticated
spectroscopic techniques to probe dynamics in complex systems. But chemistry is
not ...
45. 10%PHYS 314 - Controlling the ablation of materials with pairs of
femtosecond laser pulses
... . Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor
Street, Chicago, IL 60607 We report the synergistic effect of a pair of
ultrafast laser pulses on the ablation of materials and on the properties of the
resulting plasma. Using Si<111> as an example, we compare the ratio ...
46. 10%INOR 10 - Experimental visualizations by 2-D IR of water associating with
peptides and ions
... -Hung Kuo, Dmitriy Y. Vorobyev, Yung-Sam Kim, and Robin M. Hochstrasser.
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 10104
Ultrafast two-dimensional infrared spectra (2D IR) expose the structural
dynamics of the water solvation of polar bonds of various solutes. The dynamics
...
47. 10%PHYS 328 - Infrared spectroscopy of tritiated water
... , tokmakof@MIT.EDU. Department of Chemistry, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 Studies of water with
ultrafast nonlinear infrared spectroscopy have commonly used isotopically dilute
solutions, which provide a local probe of hydrogen bond dynamics. We have ...
48. 10%PHYS 335 - Photoinduced charge separation at CdSe quantum dots and Re-bipyridyl
complex interface
... Drive, Atlanta, GA 30322 Photoinduced charge separation between CdSe quantum
dots/adsorbed Re(CO)3Cl(dcbpy) complex (ReCOA) was investigated by both
ultrafast infrared and visible time resolved spectroscopy. Optical excitation of
the CdSe nanoparticle led to absorbance decrease (bleach) of three CO ...
49. 10%PHYS 302 - Watching electrons move in polymer blend photovoltaic
materials
... of photoinduced charge separation and the motion of the resulting electrons
are examined in an organic photovoltaic material with a combination of ultrafast
two-dimensional infrared and visible pump – infrared probe spectroscopy. The
carbonyl stretch of a functionalized fullerene, PCBM, is probed as ...
50. 10%PHYS 467 - Electron transfer at single CdSe/ZnS quantum dot/adsorbate
interface
... of quantum dots (QDs) in novel solar cells and because of its ability to
generate multiple excitons with one absorbed photon. Ensemble averaged ultrafast
spectroscopic studies show that photoinduced interfacial electron transfer (IFET)
between CdS or CdSe QDs and Rhodamine B molecules exhibit multi ...
51. 10%PHYS 343 - 1,2,3,4,5-Pentamethyl-cyclopentadiene dynamics probed by
photoionization
... , Brown University, 324 Brook St, Providence, RI 02912
1,2,3,4,5-pentamethyl-cyclopentadiene has, upon excitation of the 1B2 state at
4.65 eV, an ultrafast curve crossing dynamics that returns the molecule to the
ground state via the 2A1 state. Using time-resolved mass spectrometry and
photoelectron ...
52. 10%CHED 396 - Energy transfer in DNA oligomers
... the underlying causes of this photodamage. Our research is centered in
studying synthetic DNA oligonucleotides and monomers of DNA bases using
ultrafast spectroscopy to gain a greater understanding of energy transfer within
the genetic material. It is well known that the absorption of a photon of 266nm
...
53. 10%PHYS 726 - Infrared spectroscopic probes of dynamics in water, salt
solutions, reverse micelles, and membrane proteins
... reverse micelles, and membrane proteins James L. Skinner, skinner@chem.wisc.edu,
Department of Chemistry, University of Wisconsin, Madison, WI 53706 Ultrafast
and frequency-domain infrared spectroscopy can provide an excellent probe of the
structure and dynamics of condensed phase systems due to the ...
54. 10%PHYS 22 - 2-D Optical spectroscopy of photosynthetic light harvesting
complexes
... E119, Chicago, IL 60637 Two dimensional electronic spectroscopy provides
detailed information about electronic structure and electronic dynamics on
ultrafast timescales. Probing chromophores embedded within photosynthetic
complexes with this technique, we are able to observe the underlying design
principles ...
55. 10%PHYS 334 - Optimal control of photoproducts
... pulses perturb a molecule's excited state dynamics modulating the process
photochemical outcome. Combined with pulse shaping and optimal control,
ultrafast pulses provide a tool to arbitrarily modify molecular behavior.
Azobenzene is a photochromic molecule with two possible stable isomers. Upon
excitation ...
56. 10%PHYS 727 - New insight into the length and time scales of the hydrogen
bond network of liquid H2O
... of the OH stretching vibration are found to be particularly sensitive probes
of the fully resonant hydrogen bond network of liquid H 2O. Ultrafast memory
loss and energy redistribution are observed in which pure H 2O appears to be an
extremely strongly coupled system with no clear separation in relaxation ...
57. 10%PHYS 683 - Optimal control as a molecular learning tool
... in a dendritic novel macromolecule. Manipulation of excited state dynamics
has been successfully achieved using phase- and amplitude –shaped ultrafast
laser pulses. Changes on the excited state dynamics will influence the coupling
strength between donor and acceptor moieties, inducing a modulation of ...
58. 10%PHYS 527 - Ab initio simulation of the 2-D vibrational spectrum of
dimanganese decacarbonyl
... methodology of two-dimensional nuclear magnetic resonance spectroscopy and
applies it to vibrational resonances such that 2D IR can be used as an ultrafast
probe of molecular dynamics. The goal of this project is to calculate the 2D IR
spectrum of dimanganese decacarbonyl from first principles using ...
59. 10%PHYS 78 - Anionic species as electron transfer induced reaction
precursors
... -induced intra-cluster electron transfer reveals details of the dynamics
associated with free electron-neutral molecule systems. Furthermore, with an
ultrafast pump pulse the instant of electron transfer is defined with fs
precision. Time resolved probing of the transient anion intermediate affords the
...
60. 10%PHYS 97 - Optically induced dynamic magnetism in superparamagnetic
nanocrystals
... the photo excitation, the reduced ionic magnetic moments and the frustration
of the magnetic ordering among the magnetic moments resulted in the ultrafast
demagnetization. The recovery of the magnetization occurred on two different
time scales. The amplitude of the magnetization recovery showed a strong ...
61. 10%PHYS 724 - Reorientational dynamics of water molecules in anionic
hydration shells
... from the anion's shell. An analytic extended jump model is designed, which
accounts for the simulation results as well as available NMR[5] and ultrafast
spectroscopic data[6], and resolves the discrepancy between them. If time
permits, we will show how this approach can bring some insight on the structure
...
62. 10%PHYS 54 - Single-exciton optical gain using type-II semiconductor
nanocrystals
... recombination. Here, we demonstrate a practical approach for obtaining
optical gain in the single-exciton regime, which eliminates the problem of
ultrafast Auger decay. Specifically, we develop core/shell hetero-NCs that
produce efficient spatial separations between electrons and holes. The resulting
...
63. 10%COLL 78 - Molecules at aqueous interfaces
... using the interface selective methods of second harmonic and sum frequency
spectroscopies will be described. Measurements of both equilibrium and ultrafast
phenomena will be discussed. The Physical Chemistry of Environmental Interfaces
9:00 AM-1:10 PM, Monday, April 7, 2008 Morial Convention ...
64. 10%PHYS 456 - Artificial molecules
... ' should have an eigenstate spectrum in the vein of molecular orbitals. The
eigenstate spectrum of the biexciton has remained elusive due to the ultrafast
timescale of relaxation processes in quantum dots which mask observation of the
excited states. Here, we show the first, direct observation of excited ...
65. 10%COLL 126 - Visible light photooxidation of Mn complexes covalently
attached to TiO2
... of surface complexes leads to interfacial electron transfer in the
subpicosecond time scale, as indicated by mixed quantum-classical simulations
and ultrafast optical pumpterahertz probe transient measurements. Photoinduced
interfacial electron transfer is accompanied by Mn photooxidation, monitored ...
66. 10%PHYS 256 - Atomic solvation dynamics and the breakdown of linear response
... through two well-defined pathways: femtosecond photodetachment of Na –, and
photoinduced electron transfer/attachment to Na +. We find that the ultrafast
time-resolved solvation of nascent TCPs occurs ~2-3 times more rapidly following
attachment than detachment, qualitatively matching results of classical ...
67. 10%COLL 332 - Time-domain ab initio studies of photoinduced electron
dynamics at molecule-semiconductor interfaces
... -of-the-art non-adiabatic molecular dynamics techniques and implemented them
within time-dependent density functional theory in order to model the ultrafast
photoinduced processes in nanoscale materials at the atomistic level, and in
real time. The theoretical studies provide an exclusive perspective ...
68. 10%PHYS 170 - Dynamics and spectroscopy of open-shell species in water: The
ionization process
... prior to electron ejection. We use broadband transient absorption
spectroscopy to monitor the formation of radical and ion species in these
ultrafast ionization reactions. The spectroscopy and dynamics of the various
open-shell species are complicated by their interaction with the solvent,
therefore ...
69. 10%PHYS 232 - Computational spectroscopy of excited-state DNA bases
... allows direct computation of experimental spectroscopic observables. In this
contribution, we present simulations of time-resolved photoelectron and
ultrafast fluorescence spectra for various DNA bases. The experimental and
theoretical spectra are in good agreement and we use this to provide further ...
70. 10%PHYS 210 - Multiple exciton generation in semiconductor quantum dots and
applications to third generation solar photon conversion
... prediction has been confirmed by several groups using various spectroscopies
over the past few years in several types of QDs. Very efficient and ultrafast
multiple exciton generation (MEG) from absorbed single high energy photons has
been reported in PbSe, PbS, PbTe, CdSe, InAs and Si QDs. Efficient ...
71. 10%INOR 992 - Interactions of energetically proximate excited-states in
platinum(II) charge-transfer complexes
... temperature emission with solvent programmable photoluminescence and
transient absorption properties. Steady-state and time-resolved spectroscopy on
ultrafast and supra-nanosecond time scales are employed to elucidate the nature
of the excited-states exhibited by these complexes. Spectroscopy ...
72. 10%COLL 129 - Electron transfer dynamics at the ZnO (10-10) surface
... an important role in electron transfer across this surface and in electron
transport in devices featuring ZnO photoanodes. Additionally, we observe
ultrafast sub-20 femtosecond cooling of hot electrons within the ZnO conduction
band, suggesting that hot carrier transport may not be feasible in this ...
73. 10%PHYS 612 - Matching-pursuit split-operator Fourier-transform simulations
of excited state intramolecular proton transfer in
2-(2-hydroxyphenyl)-benzothiazole
... self-consistent field method. The reported results demonstrate the
capabilities of the MP/SOFT method as a valuble computational tool to study
ultrafast reaction dynamics in polyatomic systems as well as to validate
simulations of complex(nonintegrable) quantum dynamics in multidimensional model
systems ...
74. 10%COLL 53 - Photophysics of individual single-walled carbon nanotubes
... -dimensional bound electron–hole pairs), their robust and unexpectedly
unwavering single molecule fluorescence, and their excited state dynamics on
ultrafast time scales, including the quantized annihilation of electron–hole
pairs. Interfacial Electron Transfer and Solar Energy Conversion: From ...
75. 8%PHYS 317 - Toward coherent control in the nanoscale
... tools borrowed from coherent control of molecular dynamics with two goals in
mind. One is to introduce new function into nanoplasmonics, including ultrafast
elements and broken symmetry elements. The second is to develop coherent
nanoscale sources and apply them to coherent control of both molecular ...
===================
1. 100%PHYS 132 - Semiconductor quantum dot sensitized multiphoton
polymerization
PHYS 132 Semiconductor quantum dot sensitized multiphoton polymerization
Nicholas C. Strandwitz, nstrand@engineering.ucsb.edu 1, Anzar Khan 2, Shannon W.
Boettcher, sboettcher@chem.ucsb.edu 3, Alexander Mikhailovsky 3, Craig J.
Hawker, hawker@mrl.ucsb.edu 2, Thuc-Quyen Nguyen, quyen@chem.ucsb.edu 3 ...
2. 98%PRES 57 - Microreplication and design of biological architectures using
mask-directed multiphoton lithography
PRES 57 Microreplication and design of biological architectures using
mask-directed multiphoton lithography Jason B. Shear, jshear@biosci.utexas.edu,
Department of Chemistry and Biochemistry, University of Texas, 1 University
Station A5300, Austin, TX 78712 The study of model cellular systems has
benefited ...
3. 11%PHYS 569 - Unimolecular dissociation dynamics of the methylsulfonyl
radical using velocity map imaging
... of methylsulfonyl chloride. The spin-orbit state selected Cl(2P 3/2) and
Cl(2P 1/2) atomic fragments are detected via [2+1] resonance enhanced
multi-photon ionization (REMPI) at 235 nm. Using energy conservation, the total
recoil translational energy distribution allows us to determine the internal ...
4. 10%PMSE 405 - 3-D Patterning of polymeric hydrogels for cell guidance
... and trophism, such as nerve growth factor, NGF. The hydrogels have been
modified with defined spatial resolution taking advantage of advanced
multiphoton laser processing, resulting in patterned volumes of cell adhesion
separated by volumes of non-adhesion in agarose and growth factor concentration
...
5. 8%BIOL 117 - Supramolecular 2,3-dihydro-1H-benzo[D]imidazole and zinc(II)-complexes
as agents in photodynamic therapy
... techniques are being used in this study to elucidate the electronic and
steric factors influencing the DNA binding and the reactivity upon multiphoton
excitation at 800nm. Poster Session 5:00 PM-7:00 PM, Tuesday, April 8, 2008
Morial Convention Center -- Hall A, Poster Division of Biological ...
1. Femtosecond dynamic-absorption studies of intermolecular vibrational
coherence in bacteriochlorophyll and Zn–porphyrin charge-transfer dynamics
PHYS 23
Warren F. Beck, beck@chemistry.msu.edu, Kevin L. Dillman, Sanela Lampa-Pastirk,
and Katherine R. Shelly. Department of Chemistry, Michigan State University, 3
Chemistry Building, East Lansing, MI 48824
In order to determine the structural nature of the mode-specific reorganization
energy that nearly exactly balances the driving forces for primary and secondary
electron-transfer reactions in the purple-bacterial reaction center, we have
examined the low-frequency vibrational coherence arising from hindered
translational and librational intermolecular interactions in bacteriochlorophyll
and Zn(II)-porphyrin systems. The mean frequency of the intermolecular modes is
consistent with a van der Waals potential that contains large terms from the
London dispersion and dipole–dipole interactions; ion–dipole and
ion–induced-dipole interactions make dominant contributions in charge-transfer
products. We will discuss new results from the bacteriochlorophyll proteins B777
and B820 that show that ordered intermolecular interactions with first-shell
interactions with groups in the surrounding protein medium and adjacent BChl
macrocycles exhibit resonance Raman activities that are many times larger than
those from the skeletal modes of the macrocycles themselves. We will also
discuss new results from studies of Zn(II)
meso-tetrakis(N-methylpyridyl)porphyrin in polar solutions, where excited-state
intramolecular charge-transfer turns on the ion–dipole and ion–induced-dipole
interactions and produces a large change in the intermolecular mode frequency.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
------------------------------------
2. Pump-DFWM-spectroscopy on ?-carotene with shaped femtosecond pulses
PHYS 687
Jurgen Hauer, Tiago Buckup, and Marcus Motzkus, motzkus@staff.uni-marburg.de.
Fachbereich Chemie, Philipps-Universitat Marburg, Hans-Meerwein-Strasse, 35037
Marburg, Germany
Coherent control aims at influencing photochemical reaction pathways by
modulating the excitation pulse. We present a set of open loop control
experiments in which the behaviour on both the electronic ground and excited
state are manipulated. The differences between the ground,- and excited state
scenarios are discussed by the means of specific control parameters. The
molecule under investigation is all-trans-?-carotene, an important biomolecule.
Within the possible control objectives, coherently excited molecular
oscillations represent a promising subset. Due to their harmonic behaviour in
time, an intuitive control mechanism can be proposed: if an equally spaced
sequence of pulses excites a molecular vibration with a period Tvib, the
excitation can be mode selective if the subpulse spacing b is equal to Tvib. The
feasibility of this control scheme is tested on ground,- and excited state
transients by degenerate four wave mixing (DFWM) and Pump–DFWM respectively.
It is found that the ground state vibrations can be controlled and under
resonant excitation conditions even enhanced by the application of appropriately
spaced multipulses. Coherent control of excited state behaviour is achieved by
phase modulating the pump pulse, whereas the DFWM–sequence serves as a
heterodyne detection method. On the excited state however it is not the subpulse
spacing b but the relative phase c between them that proves to be the most
effective control parameter for manipulating the population dynamics.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
--------------------------------------
3. Femtosecond and picosecond X-ray spectroscopy in chemical dynamics research
PHYS 114
Christian Bressler, christian.bressler@epfl.ch, Laboratoire de Spectroscopie
Ultrarapide, Ecole Polytechnique Federale de Lausanne, ISIC-BSP, CH-1015
Lausanne, Switzerland
We will present our recent results on the light induced structural dynamics of
molecules in solution using an optical probe/X-ray probe method based on
ultrafast X-ray absorption spectroscopy. This approach was applied to
photoexcited coordination chemistry compounds next to nascent atomic radicals in
aqueous solutions. Structural changes were monitored for key processes,
including charge transfer and spin crossover processes. In a recent development,
femtosecond hard X-ray pulses have been extracted from the SLS synchrotron. We
will present our femtosecond results on photoexcited Fe(II) based spin crossover
complexes, where we follow, by ultrafast XANES, the evolution of the system from
the initially excited singlet state to the lowest excited quintet state, within
1 ps. An outlook to new sources of pulsed hard x-radiation, e.g., XFELs, will be
given.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
---------------------------------------
4. Controlling the ablation of materials with pairs of femtosecond laser pulses
PHYS 314
Robert J Gordon, rjgordon@uic.edu, Yongtao Cheng, Zhan Hu, Yaoming Liu, Ting Lu,
Sima Singha, and Tana E. Witt. Department of Chemistry, University of Illinois
at Chicago, 845 W. Taylor Street, Chicago, IL 60607
We report the synergistic effect of a pair of ultrafast laser pulses on the
ablation of materials and on the properties of the resulting plasma. Using Si<111>
as an example, we compare the ratio of the fluorescence from discrete
transitions of neutral and ionized Si produced by a pair of pulses to that
produced by a single pulse of the same total energy. We find that the
fluorescence enhancement ratio increases with the delay between the pulses and
decreases with the total pulse energy. We explain these results by a mechanism
in which the first pulse melts the surface to produce a nanoscale liquid film,
and the second pulse is absorbed more strongly by the molten phase. This
mechanism is supported by reflectivity and AFM measurements. Similar behavior is
observed for Cu, whereas qualitatively different trends are observed for a
variety of dielectrics. We further observe for Si that the fluorescence is
strongly polarized. The polarization increases with delay and pulse energy and
decreases with wavelength for discrete as well as continuum emission. Under
appropriate conditions, greater than 90% polarization was observed, suggesting
strong anisotropy of the plasma.
Spectroscopy, Chemistry, and Imaging through Nanophotonics
1:20 PM-5:20 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm.
340/341, Oral
Division of Physical Chemistry
---------------------------------------
5. Photoinduced and dark bimolecular reactions in aqueous solutions of ruthenium
(II)-tris-(2,2'-bipyridine) upon high intensity femtosecond laser excitation
INOR 934
Alexander N. Tarnovsky, atarnov@bgsu.edu, Department of Chemistry & Center for
Photochemical Sciences, Bowling Green State University, Bowling Green, OH 43403
The structures of reaction intermediates can be obtained using a novel laser
pump/x-ray absorption probe technique (tr-XAS), in which high spatial resolution
of x-ray probe radiation is combined with high temporal resolution of
femtosecond laser photoexcitation. For reconstruction of the local structures
from tr-XAS, the knowledge of product yields under high intensity
photoexcitation conditions is required. Considerable efforts have been made to
describe the photophysics and photochemistry of [RuII(bpy)3]2+ complex, which is
a model system for metal-to-ligand charge transfer reaction as well a prototype
of d6 polypyridine complexes of second-row transition metals. Recent tr-XAS
experiments on aqueous [RuII(bpy)3]2+ with 50-ps time resolution have provided
structural information on the complex in the 3MLCT triplet excited state. Very
few studies of this complex, however, dealt with issues of high excitation
intensities and large solute concetrations. Here, we discuss a femtosecond
pump-probe investigation of the photochemistry of [RuII(bpy)3]2+ (°U20 mM) in
aqueous solutions initiated by excitation with 400 nm, ~130 fs laser pulses of
high power density (up to 2 TW cm-2). Transient absorption difference spectra in
the 345?C660 nm range measured with delay times of up to 1 ns at various energy
fluence enable observation of the following photoproducts: the complex in the
3MLCT triplet excited state, the reduced form [RuII(bpy)3]+, the oxidized form
[RuIII(bpy)3]3+, and the hydrated electron eaq. The product formations
mechanisms are discussed.
Spectroscopy of Inorganic Systems
2:00 PM-5:25 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 219,
Oral
Division of Inorganic Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
----------------------------------------
6. Ultrafast dynamics in single-walled carbon nanotubes
PHYS 303
David J. Styers-Barnett1, Brian P. Mehl1, Brittany C. Westlake, westlake@email.unc.edu2,
and John M. Papanikolas, john_papanikolas@unc.edu1. (1) Department of Chemistry,
University of North Carolina, Chapel Hill, NC 27599, (2) Department of
Chemistry, University of North Carolina at Chapel Hill, Caudill and Kenan
Laboratories, Chapel Hill, NC 27599-3290
We have used femtosecond transient absorption spectroscopy to examine the
excited state dynamics of single-walled carbon nanotube (SWNT) bundles embedded
in polymer matrices. The SWNTs are excited by a femtosecond pump pulse and
probed using a white-light continuum. We observe a structured transient
absorption spectrum consisting of a series of narrow induced transmission (IT)
and induced absorption (IA) bands, which appear on a time scale shorter than our
instrument response (200 fs) and persist for up to 100 ps. Analysis of the
transient absorption spectra suggests that the narrow features are the result of
a nonlinear optical response in the SWNTs. The induced absorption bands are
attributed to biexciton formation in which a second electron-hole pair is formed
in close proximity to already existing exciton, producing a four-particle
excitation. Transient absorption spectra obtained at a series of pump-probe
delay times reflect the exciton dynamics following excitation.
Optical Probes of Dynamics in Complex Environments
1:20 PM-5:20 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-----------------------------------------
7. Ultrafast magnetization dynamics in cobalt-doped iron oxide nanocrystals:
Effect of varying exchange interaction
PHYS 341
Chih-Hao Hsia, chhsia@mail.chem.tamu.edu, Tai-Yen Chen, tychen@mail.chem.tamu.edu,
and Dong Hee Son, dhson@mail.chem.tamu.edu. Department of Chemistry, Texas A&M
University, College Station, TX 77842
The dynamics of photo-induced magnetization in chemically synthesized Co-doped
iron oxide nanocrystals were investigated by femtosecond Faraday rotation
measurements. Through the controlled doping of Co, nanocrystal samples of
varying Co content were prepared ranging from Fe3O4 to CoFe2O4. The effect of Co
doping, which influences the exchange interaction between the ionic magnetic
moments, on the dynamics of the demagnetization and its recovery were
investigated. The time scale and the amplitude of the changes in magnetization
following the spin flip excitation were dependent on Co content. The amplitude
of the time-dependent differential magnetization was correlated with the spin
coherence length, which increases with the strength of the exchange interaction.
PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Sci-Mix
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
------------------------------------------
8. Charge transfer induced proton-coupled electron transfer
PHYS 331
Jared J. Paul, jpaul@unc.edu, Brittany C. Westlake, westlake@email.unc.edu, M.
Kyle Brennaman, kyleb@email.unc.edu, John M. Papanikolas, john_papanikolas@unc.edu,
and Thomas J. Meyer, tjmeyer@email.unc.edu. Department of Chemistry, University
of North Carolina at Chapel Hill, Caudill and Kenan Laboratories, Chapel Hill,
NC 27599-3290
The relaxation dynamics of a photoexcited hydrogen bound
4-hydroxy-4'-nitrobiphenyl and t-butylamine association complex have been
followed using both femtosecond and nanosecond transient absorption
spectroscopy. Upon photoexcitation, the biphenyl molecule undergoes an
intramolecular transition that transfers charge from the hydroxy end of the
molecule to the nitro- end. Ultrafast measurements show direct evidence that
relaxation to ground state (i.e. back electron transfer) is coupled to proton
transfer from the hydroxyl group to the base. Partitioning to a second path
involving dissociation of the hydrogen-bonded complex to give a deprotonated
form is shown through nanosecond transient absorption spectroscopy.
PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Sci-Mix
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
--------------------------------------------
9. Ultrafast coherent plasmon dynamics of individual metal nanostructures
PHYS 445
Alexandria Kappus, alex63@u.washington.edu, C. C. Neacsu, neacsu@u.washington.edu,
and M. B. Raschke, raschke@chem.washington.edu. Department of Chemistry,
University of Washington, 36 Bagley Hall, Seattle, WA 98195
The coherent electron dynamics in metal nanostructures, with a temporal response
as short as just several femtoseconds, controls local field enhancement as well
as excitation and quenching of coupled molecular excitations. To avoid the
heterogeneous broadening of ensemble measurements it is desirable to perform
corresponding studies on the single particle level. Here, we demonstrate the
resonant and off-resonant coherent dynamics of the plasmon response of
individual, clean and adsorbate covered gold nanotips. We use second-harmonic
interferometric autocorrelation with sub-10 fs excitation. The femtosecond
temporal response of the plasmon polariton is found to be sensitive with respect
to the structural parameters of the tips in terms of apex radius and cone angle
and can be described by quasi-static model calculations.
PHYS Poster Session - Nanostructured Materials and Nanophotonics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Sci-Mix
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
---------------------------------------------
10. Photopolymerization of conductive metal nanoparticles
PHYS 506
Xichen Cai, xichenc@bgsu.edu, Kelechi C Anyaogu, akelech@bgnet.bgsu.edu, and
Douglas C. Neckers, neckers@photo.bgsu.edu. Center for Photochemical Sciences,
Bowling Green State University, 132 Overman Hall, Bowling Green, OH 43403
Polymeric conductive nanomaterials are expected to have various applications as
chemical or biosensors, in transistors and switches, as photovoltaic cells,
electrochromic devices, and optically conducting materials. However, the
synthesis of conductive nanomaterials in a desired two- or three-dimensional
structure remains a challenge. In general, chemical and electrochemical
polymerization are common methods to produce conducting polymers in which
nanoparticles (NPs) are embedded. We report herein the photopolymerization of
5-mercapto-2,2'-bithiophene (BTSH) functionalized metal (Au, Ag, and Cu) NPs.
The three-dimensional structure of aggregated NPs was identified using
transmission electron microscopy (TEM) and scanning electron microscopy (SEM).
Electron transfer from ligand to metal was confirmed by femtosecond transient
absorption measurements. Ligand radical cation coupling caused the linking of
the metal nanoparticles. Photopolymerization of BTSH functionalized metal NPs
provides a useful method for making two- or three-dimensional designs of
conductive polymeric nanomaterials.
PHYS Poster Session - Nanostructured Materials and Nanophotonics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Sci-Mix
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
----------------------------------------------
11. Ultrafast dynamics at the air/water interface investigated with
time-resolved electronic sum-frequency generation (TR-ESFG) spectroscopy
PHYS 351
Kentaro Sekiguchi, ksekiguchi@riken.jp, Shoichi Yamaguchi, shoichi@riken.jp, and
Tahei Tahara, tahei@riken.jp. Molecular Spectroscopy Laboratory, RIKEN (The
Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama, Japan
We developed a new surface-selective time-resolved nonlinear spectroscopy,
femtosecond time-resolved electronic sum-frequency generation (TR-ESFG)
spectroscopy, to investigate ultrafast dynamics at liquid interfaces. Its
advantage over conventional time-resolved second harmonic generation
spectroscopy is that it provides spectral information, which is realized by the
multiplex detection of the sum frequency signal using a broadband white light
continuum and a multichannel detector. With this new method, we examined the
photo-induced dynamics of a surface active dye (rhodamine 800) at the air/water
interface and successfully observed transient electronic spectra of interfacial
molecules for the first time. We found that the relaxation dynamics exhibited
three time constants of 0.32 ps, 6.4 ps, and 0.85 ns, and the 6.4-ps component
corresponds to an interface-specific deactivation process. With the TR-ESFG
spectroscopy, we can now investigate dynamics at liquid interface as thoroughly
as we do for the dynamics in bulk solutions with the conventional femtosecond
time-resolved absorption spectroscopy.
PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
----------------------------------------------
12. Ultrafast dynamics in the MLCT excited states of Ru(II) and Os(II)
coordination complexes
INOR 985
John M. Papanikolas, john_papanikolas@unc.edu, Department of Chemistry,
University of North Carolina, Chapel Hill, NC 27599
We have used femtosecond transient absorption spectroscopy to address the
fundamental photophysics of metal-to-ligand charge-transfer (MLCT) excited
states in both symmetric and asymmetric (i.e. mixed-ligand) complexes. We have
examined the flow of energy between a chromophore and ligand bound energy
acceptor, from one ligand to another (i.e. ILET), and between two fragments on
the same ligand. Our experiments have touched on vibrational cooling,
intersystem crossing, and excited state solvation. They have led to a detailed
picture of the excited state potentials in polar solvents, provided insight into
the nature of the excited state wavefunctions, and the partitioning of excess
optical excitation energy between molecular vibrations (inner sphere) and
solvent interactions (outer sphere).
Spectroscopy of Inorganic Systems
9:00 AM-1:20 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. R03,
Oral
Division of Inorganic Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-----------------------------------------------
13. Advances in structural analyses of complex molecules
INOR 35
Keith O. Hodgson, Department of Chemistry and Stanford Synchrotron Radiation
Laboratory, Stanford University, Stanford, CA 94309
Structural characterization has played a seminal role in our understanding of
the function and reactivity of metal ion sites in many bioinorganic systems.
Crystallography and x-ray absorptionspectroscopy have contributed greatly in
this regard, especially to understanding of complex multicomponent enzyme
systems like nitrogenase. Several examples will be used to illustrate the
current "state of the art". The field is poised for major new developments in
x-ray studies with the coming of the world's first x- ray free electron laser
sources like the LCLS at Stanford in the next few years. Such x-ray beams will
have much higher peak brightness (more than 10**10 and shorter
pulses(femtosecond rather than picosecond regime) than currently available.
Examples will be used to illustrate the potential of this new class of sources
for study of structural dynamics on the femtosecond time scale.
Celebrating Bioinorganic, Supramolecular, Lanthanide and Actinide Chemistry with
Ken Raymond
8:30 AM-1:15 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 218, Oral
Division of Inorganic Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
--------------------------------------------------
14. First-principles approach to the anharmonic vibrational properties of
biomolecules
PHYS 166
Jianping Wang, jwang@iccas.ac.cn, Kaicong Cai, Xiaoyan Ma, and Guixiu Wang.
Molecuar Dynamics Laboratory, Institute of Chemistry, Chinese Academy of
Sciences, No. 2 1st North St. Zhongguancun, Haidian District, Beijing, 100080,
China
Femtosecond two-dimensional infrared (2D IR) spectroscopy can be used to monitor
structures and dynamics of molecules in condensed phases by mapping out
time-dependent vibrational couplings. The framework of a 2D IR spectrum is
anharmonic vibrational motions. Very recently we have shown that all the
diagonal and mixed-mode anharmonicities of the 3N-6 modes of a molecular system
can be obtained by first-principles computations and based on which all-mode 1D
and 2D IR spectra can be simulated. In this work, we further examine the
anharmonic vibrational parameters of biomolecules, including peptides, nucleic
acids, lipids, as well as sugars, using the first-principles approach. A
polarizable continuum model is used to provide implicit solvent environment for
the biomolecules. The characteristics of the structure-dependent anharmonic
parameters are discussed.
Optical Probes of Dynamics in Complex Environments
1:20 PM-5:20 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 344, Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
---------------------------------------------------
15. Elucidation of mechanism following adaptive control of complex molecules in
solution
PHYS 682
Niels H. Damrauer, niels.damrauer@colorado.edu, Matthew A. Montgomery,
matthew.montgomery@colorado.edu, and Erik M. Grumstrup. Department of Chemistry
and Biochemistry, University of Colorado at Boulder, Campus Box 215, Boulder, CO
80309
The significance of adaptive femtosecond pulse shaping stems from the use of
iterative learning which allows for the control and study of electronically,
structurally, and reactively complex systems. This presents a remarkable
opportunity for chemists to ask what can be done and learned if light were a
controllable reagent. Significant progress has been made but the field's
development into a viable interrogative tool requires the new methods to extract
mechanistic information about control following unbiased many parameter adaptive
searches. Recent efforts in our laboratory have involved adaptive control of
photoinduced electron transfer phenomena in transition metal coordination
complexes in solution. This talk will discuss progress uncovering control
surfaces from statistical analyses of adaptive control results. Such surfaces
underscore the molecular system's response to the laser field and can be used to
test mechanistic hypotheses.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
----------------------------------------------------
16. Probing quasiparticle and electron correlations by coherent 2-D spectroscopy
PHYS 164
Shaul Mukamel, smukamel@uci.edu, Darius Abramavicius, Lijun Yang, Zhenyu Li, and
Rafal Oszwaldowski. Department of Chemistry, University of California, Irvine,
1102 Natural Sciences II, Irvine, CA 92697-2025
Sequences of femtosecond optical pulses are designed to generate signals that
are induced by correlations among elementary excitations. Applications to
Frenkel excitons in photosynthetic complexes, Wannier excitons in semiconductor
quantum dots and wells, and electrons in molecules will be presented. Specific
phase-matching directions can target the correlated dynamics of double
excitations. Cross peaks in 2D correlation plots are interpreted in terms of
quasiparticle scattering. They reveal the double-exciton wavefunction, projected
into products of single-excitons. Uncorrelated double-exciton states do not show
up in the spectra due to quantum interference among pathways. The proposed
techniques amplify cooperative dynamical features and reveal information on the
robustness of quantum states to fluctuating environments.
Optical Probes of Dynamics in Complex Environments
1:20 PM-5:20 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 344, Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
----------------------------------------------------
17. Optimal control of photoproducts
PHYS 334
Daniel G. Kuroda, dkuroda@chem.ufl.edu, Department of Chemistry, University of
Florida, PO Box 117200, Gainesville, FL 32603 and Valeria D. Kleiman, kleiman@chem.ufl.edu,
Department of Chemistry, Center for Chemical Physics, University of Florida, PO
BOX 117200, Gainesville, FL 32611-7200.
We investigate the coherent control of azobenzene's excited state population
dynamics by adaptive pulse shaping.
Femtosecond excitation pulses perturb a molecule's excited state dynamics
modulating the process photochemical outcome. Combined with pulse shaping and
optimal control, ultrafast pulses provide a tool to arbitrarily modify molecular
behavior. Azobenzene is a photochromic molecule with two possible stable
isomers. Upon excitation, the molecule evolves in the excited surface in a
picosencond time scale. Multiple pathways can lead azobenzene back to the ground
state. While one pathway produces isomerization, the other one relaxes the
system to its initial isomeric form.
The effect excitation pulse modulation has on the deactivation pathways can be
followed by measuring ground state bleach. Any changes observed in the
population recovery indicate control over the system dynamics. By varying the
phase modulation of the excitation pulse we investigate the excited state
dynamics and its role in the isomerization process.
PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
------------------------------------------------------
18. Ultrafast dynamics of electron transfer and solvation processes at ammonia
and water ice/metal interfaces
COLL 123
Martin Wolf, wolf@physik.fu-berlin.de, Dept. of Physics, Freie Universitaet
Berlin, Arnimallee 14, Berlin, 14195, Germany
The ultrafast dynamics of interfacial electron transfer are studied for
ultrathin ice and ammonia layers adsorbed on Cu(111) and Ru(001) surfaces using
femtosecond time- and angle resolved two-photon-photoemission (2PPE)
spectroscopy. In this process, photo-injection of electrons from the metal into
the conduction band is followed by ultrafast localization and solvation of the
excess electron. The subsequent energetic stabilization of these solvated
electrons due to nuclear rearrangements of the polar molecular environment is
accompanied by an increasing degree of localization. The solvation dynamics is
found to strongly depend on the adlayer structure, which can be controlled by
the growth conditions and the choice of different substrates as a template. In
this talk I will compare the solvation dynamics in several types of ammonia and
water adlayers and discuss, in particular, the influence of adsorbate structure,
the question of bulk versus surface solvation as well as the role of thermally
assisted tunnelling on the electron transfer.
Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to
Nanomaterials
2:00 PM-6:00 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 226, Oral
Division of Colloid & Surface Chemistry
------------------------------------------------------
19. Ultrafast 1- and 2-D infrared studies of complex chemical reactions
PHYS 250
Charles B. Harris, cbharris@berkeley.edu, Karma R. Sawyer, karma@berkeley.edu,
James F. Cahoon, jfcaho@berkeley.edu, and Jacob P. Schlegel. Department of
Chemistry, University of California at Berkeley, Berkeley, CA 94720
Femtosecond infrared spectroscopy is a valuable experimental tool for
investigating the details of complex chemical reactions in ambient solution.
UV-pump, IR-probe spectroscopy is first used to elucidate the sequential steps
in complex chemical reactions. Transient two-dimensional infrared spectroscopy
is then applied to reveal more detailed information about the reactions
including the transformation of vibrations from reactants through intermediates
to products, molecular anharmonicities and the structure of short-lived
transients. The applications of both techniques to the elucidation of complex
reaction mechanisms in prototypical organometallic reactions and some important
homogeneous catalysis reactions will be discussed.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-------------------------------------------------------
20. Watching the protein mambo: Spectroscopic probes of enzyme dynamics
PHYS 204
Christopher M. Cheatum, christopher-cheatum@uiowa.edu, Jigar N. Bandaria,
jigar-bandaria@uiowa.edu, Sarah E. Hill, sarah-hill@uiowa.edu, Samrat Dutta,
samrat-dutta@uiowa.edu, and Amnon Kohen. Department of Chemistry, University of
Iowa, Iowa City, IA 52242
The structural dynamics of enzymes at the femtosecond to picosecond time scale
have been invoked to explain the results of temperature-dependent
kinetic-isotope-effect measurements for a number of enzymatic reactions. We
report studies of enzyme-ligand interaction dynamics at this time scale. To
identify the residues that control the dynamics, we have probed the fluctuations
of isozymes and mutants of human carbonic anhydrase. We have also studied enzyme
dynamics in a transition-state-analog complex for the enzyme formate
dehydrogenase. Our results support a potential role for fast dynamics near the
transition state and reveal differences in the nature of enzyme-ligand
interaction dynamics in the ground state and in vicinity of the transition state
of a reaction.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Tuesday, April 8, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
--------------------------------------------------------
21. Nanoparticle induced light-harvesting membrane protein deformation (LH2)
revealed by ultrafast spectroscopic study of the excitonic states
PHYS 25
Yu-Xiang Weng, yxweng@aphy.iphy.ac.cn, Laboratory of Soft Matter Physics,
Institute of Physics, Chinese Academy of Sciences, Hai Dian Qu Zhong Guan Cun
Nan San Jie 8 Hao, Beijing, 100080, China
We used femto-second time resolved transient absorbance difference spectroscopy
to investigate the membrane protein of a light-harvesting antenna complex (LH2)
from photosynthetic bacteria Rb. sphaeroides 2.4.1, which consists of two
concentric polypeptide cylinders and ringlike pigment aggregate (B850). The
deformation of the protein was induced by self-assembly of LH2 onto
nanoparticles of different size. The results show that when size of the
nanoparticle approaches the diameter of either the inner or the outer
polypeptide cylinder, it would induce a largest protein deformation, giving rise
to a shorter excited-state life time of B850. This provides a quantitative
example of size-matching interaction between the protein and the nanopartilces.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-----------------------------------------------------
22. Long-range proton transfer in aqueous acid-base reactions
PHYS 723
Bradley J. Siwick, bradley.siwick@mcgill.ca1, Jocelyn Cox2, and Huib J. Bakker,
bakker@amolf.nl2. (1) Departments of Chemistry and Physics, McGill University,
801 Sherbrooke St. West, Montreal, QC H3A 2K6, Canada, (2) FOM - AMOLF,
Kruislaan 407, 1098 SJ Amsterdam, Netherlands
We have investigated the mechanism of proton transfer (PT) between the
photo-acid 8-hydroxy-1,3,6-pyrenetrisulfonic acid (HPTS) and acetate in aqueous
solution by probing the vibrational resonances of HPTS, acetate and the hydrated
proton with femtosecond mid-infrared laser pulses. We find that PT in this model
system takes place in a distribution of hydrogen-bound reaction complexes that
differ in the number of water molecules separating the acid and the base. The
number of intervening water molecules ranges from 0 to 5, which together with a
strongly distance-dependent PT rate explains the observed highly non-exponential
reaction kinetics. The kinetic isotope effect for the reaction is determined to
be 1.5, indicating that tunneling does not play a significant role in the
transfer of the proton. Rather, the transfer mechanism is best described in
terms of the adiabatic proton transfer picture as it has been formulated by J.
T. Hynes and coworkers, where solvent fluctuations play an essential role in
forming the correct hydrogen-bond configuration and solvent polarization to
facilitate PT.
Optical Probes of Dynamics in Complex Environments
1:20 PM-5:00 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
------------------------------------------------------
23. Taking it to the limit: Ultrafast dynamics of heat transport over ultrasmall
distances
PHYS 301
Jeffrey A. Carter, jcarter3@uiuc.edu, Zhaohui Wang, and Dana D. Dlott.
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL
61801
We have developed a new method for studying the propagation of energy into and
through molecules using an ultrafast heat bath.1 The heat bath, a gold
substrate, is flash-heated up to 1000 K in approximately 1 ps with a femtosecond
laser pulse. A self-assembled monolayer, attached to the heat bath at one end by
a Au-S bond, heats as thermal energy surges into the molecules. The resulting
dynamics are monitored with picosecond resolution using vibrational
sum-frequency generation (SFG) spectroscopy. Due to the coherent nature of the
SFG response, the presence of thermal disorder with the monolayer can be
observed.
This material is based upon work supported by the National Science Foundation
under award DMR 0504038 and the Air Force Office of Scientific Research under
award FA9550-06-1-0235.
1. Z. Wang, et al. Science. 317. 787 (2007)
Optical Probes of Dynamics in Complex Environments
1:20 PM-5:20 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
--------------------------------------------------------
24. Ultrafast infrared spectroscopy of dilute HOD in aqueous salt solutions
PHYS 620
Yu-Shan Lin, lin5@wisc.edu, Department of Chemistry, University of Wisconsin -
Madison, 1101 University Ave, Madison, WI 53706-1322 and J. L. Skinner, skinner@bert.chem.wisc.edu,
Department of Chemistry, University of Wisconsin, Madison, WI 53706.
Water structure and dynamics in the solvation shells of solutes play an
important role in aqueous chemistry. The direct measurement of the dynamics of
water molecules in the first solvation shells of Cl-, Br- and I- has been
achieved recently by femtosecond midinfrared nonlinear spectroscopy. The
previous approach of the electronic structure/molecular dynamics (ES/MD) method
for calculating ultrafast vibrational spectroscopy observables is extended to
treat multi-species systems. Using this extended ES/MD method, we examined the
infrared lineshapes and frequency time-correlation functions for dilute HOD in
aqueous salt solutions. The effects of the nature of ions and the salt
concentration on the hydrogen bond dynamics are studied and the calculated
spectroscopic observables are compared with the experimental results.
PHYS Poster Session - Computational Spectroscopy and Reaction Dynamics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-------------------------------------------------
25. Simulations of coherent exciton dynamics in multidimensional spectroscopy
PHYS 183
Darius Abramavicius, dariusa@uci.edu1, Dmitri Voronine, voronine@uci.edu1, and
Shaul Mukamel, smukamel@uci.edu2. (1) Department of Chemistry, University of
California, Irvine, 1102 Natural Sciences II`, Irvine, CA 92697-2025, (2)
Department of Chemistry, University of California Irvine, 1102 Natural Sciences
II, Rowland Hall 434, Irvine, CA 92697-2025
A computational algorithm based on the nonlinear exciton equations is presented
for simulating and interpreting the response of chromophore aggregates to
sequences of femtosecond laser pulses. Applications are made to the Fenna-Matthews-Olson
(FMO) light harvesting complex. Some fundamental symmetries of multidimensional
optical signals are used to design techniques that can selectively resolve
coherent quantum dynamics and incoherent energy dissipation. Simulations show
damped oscillations of cross peaks corresponding to evolution of coherences,
without interference from incoherent population relaxation. Energy transfer
pathways are seen through the redistribution of crosspeak amplitudes. Resolution
is enhanced by employing specific pulse polarization configurations to generate
chirality–induced signals.
Computational Spectroscopy
8:00 AM-12:00 PM, Tuesday, April 8, 2008 Morial Convention Center -- Rm. 342,
Oral
Division of Physical Chemistry
-------------------------------------------------
26. Resolving the excited and ground state
reaction coordinates in the green fluorescence protein and mutants with
dispersed pump-dump probe spectroscopy
PHYS 24
Delmar S. Larsen, dlarsen@ucdavis.edu1,
Jie Pan, jiepan@ucdavis.edu1, Mikas Vengris, Mikas.Vengris@ff.vu.lt2, Deborah
Stoner-Ma, dstonerma@hotmail.com3, and Peter J. Tonge, peter.tonge@sunysb.edu4.
(1) Department of Chemistry, University of California, Davis, One Shields Ave,
Davis, CA 95616, (2) Dept. of Chemistry, University of California, Davis, One
Shields Ave, Davis, 95616, (3) Department of Chemistry, Stony Brook University,
Nicholls Road, Stony Brook, NY 11794-3400, (4) Department of Chemistry, SUNY
Stony Brook, Stony Brook, NY 11794-3400
The excited- and ground-state photodynamics of wild-type (wt), S65T/H148D and
S65T/H148E mutants of the Green Fluorescent Protein (GFP) system were
characterized with femtosecond time-resolved dispersed multi-channel
pump-dump-probe measurements. Discrete transient intermediates with specific
spectral properties are identified to describe the evolution in the mutant
variants with greater complexity than in wt-GFP. For the first time, excited-
and ground state structural evolution of the chromophore is observed as
non-stationary dumping kinetics. The proton transfer kinetics observed in wt-GFP
is accelerated two orders of magnitude faster in S65T/H148D presumably due to a
low-barrier hydrogen bond between the intrinsic chromophore and the introduced
aspartate residue. Modification with glutamate residue in S65T/H148E decreases
the proton transfer kinetics by 2 orders of magnitude. These results are
discussed in terms of the geometry of the residues surrounding the chromophore.
Dump induced signals resolve a bifurcation of the proton transfer kinetics
resulting in multiple resting spots.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
---------------------------------------------------
27. Hidden electronic excited state of enhanced green fluorescent protein (eGFP)
by new multiplex two-photon absorption spectroscopy
PHYS 27
Haruko Hosoi, haru@riken.jp1, Shoichi Yamaguchi1, Hideaki Mizuno2, Atsushi
Miyawaki2, and Tahei Tahara1. (1) Molecular Spectroscopy Laboratory, RIKEN (The
Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, 351-0198,
Japan, (2) Brain Science Institute, RIKEN (The Institute of Physical and
Chemical Research), 2-1 Hirosawa, Wako, 351-0198
We have newly developed non-degenerate two-photon absorption (TPA) spectroscopy,
which enables us to measure precise TPA spectra for a broad wavelength range,
utilizing narrow-band and broad-band femtosecond pulses with multichannel
detection. We applied this technique to study the electronic structure of
enhanced green fluorescent protein (eGFP), which is the most widely used GFP as
a fluorescent probe for bioimaging. The observed TPA spectrum is significantly
blue-shifted compared with its one-photon absorption spectrum although the
chromophore of eGFP has no inversion symmetry. The result indicates the
existence of a “hidden” excited state in the vicinity of the lowest excited
singlet state. We conclude that this is the origin of the discrepancy between
the one-photon and two-photon excitation spectra of eGFP, which is well known in
the field of biology.
Optical Probes of Dynamics in Complex Environments
8:00 AM-12:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 344,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
---------------------------------------------------
28. Infrared spectroscopy of tritiated water
PHYS 328
Rebecca A. Nicodemus, nicodemu@mit.edu, Lauren DeFlores, and Andrei Tokmakoff,
tokmakof@MIT.EDU. Department of Chemistry, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139
Studies of water with ultrafast nonlinear infrared spectroscopy have commonly
used isotopically dilute solutions, which provide a local probe of hydrogen bond
dynamics. We have studied the infrared spectroscopy of tritiated water, as a
step toward probing hydrogen bond switching with correlation spectroscopy
between the OD and OT stretching vibrations in H2O. We report on the infrared
absorption spectrum and femtosecond infrared pump-probe spectroscopy of the OT
stretching vibration of HOT in H2O. We compare IR absorption line shape
parameters between the three isotopes (OH:OD:OT), discussing deviations from
harmonic scaling relationships in terms of electrical and mechanical
anharmonicity. Comparison of the lifetimes between the three isotopes, obtained
from pump-probe experiments, gives valuable information on the vibrational
relaxation pathways in water.
PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-----------------------------------------------------
29. Multiple exciton generation in semiconductor quantum dots and applications
to third generation solar photon conversion
PHYS 210
Arthur J. Nozik, anozik@nrel.gov1, Randy J. Ellingson2, Matthew C. Beard,
matthew_beard@nrel.gov3, Joseph Luther, joseph_luther@nrel.gov3, Justin C.
Johnson3, Matthew D Law4, and Qing Song4. (1) NREL, 1617 Cole Blvd, Golden, CO
80401, (2) Energy Sciences, National Renewable Energy Laboratory, 1617 Cole
Blvd, Golden, CO 80401, (3) Center for Basic Sciences, National Renewable Energy
Laboratory, 1617 Cole Blvd., Golden, CO 80401, (4) Energy Sciences, NREL, 1617
Cole Blvd, Golden, CA 80401
In order to utilize solar power for the production of electricity and fuel on a
massive scale, it will be necessary to develop solar photon conversion systems
that have an appropriate combination of high efficiency (delivered watts/m2) and
low capital cost ($/m2). One potential, long-term approach to high efficiency is
to utilize the unique properties of quantum dot nanostructures to control the
relaxation dynamics of photogenerated carriers to produce either enhanced
photocurrent through efficient photogenerated electron-hole pair multiplication
or enhanced photopotential through hot electron transport and transfer. To
achieve these desirable effects it is necessary to understand and control the
dynamics of hot electron and hole relaxation, multiple exciton generation,
cooling, charge transport, and interfacial charge transfer of the photogenerated
carriers with femtosecond (fs) to ns time resolution. We have been studying
these fundamental dynamics in various bulk and nanoscale semiconductors (quantum
dots (QDs), quantum rods/wires, and quantum wells)using fs - ns transient
absorption, photoluminescence, and THz spectroscopy. Recently, we predicted the
generation of more than one electron-hole pair (exciting as excitons in QDs) per
absorbed photon would be an efficient process in QDs . This prediction has been
confirmed by several groups using various spectroscopies over the past few years
in several types of QDs. Very efficient and ultrafast multiple exciton
generation (MEG) from absorbed single high energy photons has been reported in
PbSe, PbS, PbTe, CdSe, InAs and Si QDs. Efficient MEG may greatly enhance the
conversion efficiency of solar cells that incorporate QDs for both solar
electricity and solar fuel (e.g., H2) production. Aspects of this work will be
summarized and recent advances will be discussed. Various configurations for
quantum dot solar cells for ultrahigh conversion efficiencies for the production
of electricity and solar fuels will be presented, along with progress in
developing such new types of solar cells.
Spectroscopy, Chemistry, and Imaging through Nanophotonics
8:00 AM-12:00 PM, Tuesday, April 8, 2008 Morial Convention Center -- Rm. 345,
Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
---------------------------------------------------------
30. New insights into electronic structures of semiconductor nanocrystals
through single-particle and ultrafast spectroscopies
PHYS 318
Victor I. Klimov, Chemistry Division, Los Alamos National Laboratory, MS-J567,
Los Alamos, NM 87545
Semiconductor nanocrystals are stable, spectrally tunable chromophores with
potential applications in areas such as solid-state lighting, lasing,
photovoltaics, and bio-labeling. Realization of these applications requires deep
understanding of electronic structures and mechanisms for light-matter
interactions in nanocrystalline materials. To elucidate the mechanisms for light
absorption/ emission, we apply a combination of various single-particle and
ultrafast spectroscopic techniques. For example, we use single-nanocrystal
photoluminescence (PL) excitation spectroscopy in conjunction with femtosecond
time-resolved PL to study the structure of band-edge optical transitions and
mechanism for intraband relaxation. Further, we apply single-nanocrystal
magneto-PL to investigate the spin structure of emitting states and interplay
between effects such as the Zeeman splitting and the long-range exchange
interaction. Finally, we use photon correlation spectroscopy to conduct
quantum-optical studies of single- and multiexciton states in nanocrystals.
Spectroscopy, Chemistry, and Imaging through Nanophotonics
1:20 PM-5:20 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm.
340/341, Oral
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-------------------------------------------------------------
31. Charge transfer excitons on a crystalline organic semiconductor surface
COLL 328
Matthias Muntwiler, muntwiler@chem.umn.edu and X-Y. Zhu, zhu@chem.umn.edu.
Department of Chemistry, University of Minnesota, 207 Pleasant St SE,
Minneapolis, MN 55455
Organic heterojuction photovoltaic cells rely on the dissociation of excitons at
donor-acceptor interfaces. Such interfacial exciton dissociation does not
necessarily result in charge carriers. Due to the low dielectric constant of a
typical organic semiconductor material, electrostatic interaction between an
electron and a hole is sufficiently long ranged, on the order of a few to a few
tens of nanometers. This leads to the formation of a weakly bound geminate pair,
i.e., a charge transfer(CT) exciton, which keeps the electron and the hole in
close proximity and significantly increases the possibility of charge
recombination. Although such geminate pairs or CT excitons have been proposed,
there is little experimental evidence of these transient species. Here, we
report the observation of CT excitons on the surface of a crystalline organic
semiconductor, pentacene, from femtosecond time-resolved two-photon
photoemission spectroscopy. In this model system, pentacene is the electron
donor and vacuum is the “electron acceptor”. The excited electron in a CT
exciton state is bound by two contributions: electronic polarization of the
pentacene surface and the electrostatic attraction from the hole. The binding
energies of the two observed CT excitons are BE = 0.87 (n = 1) and 0.44 eV (n =
2), with transient lifetimes of 70 fs and 130 fs, respectively. The implications
of these CT excitons in organic heterojunction photovoltaic process are
discussed.
Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to
Nanomaterials
2:00 PM-5:40 PM, Tuesday, April 8, 2008 Morial Convention Center -- Rm. 226,
Oral
Division of Colloid & Surface Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-----------------------------------------------------------
32. nfrared pump-probe investigation of melanin vibrational relaxations
CHED 988
Aaron Massari1, Sarah A. Weinreis, saweinre@mtu.edu2, and Audrey A. Eigner,
eigner@chem.umn.edu1. (1) Department of Chemistry, University of Minnesota,
Minneapolis, MN 55455, (2) Department of Chemistry, Michigan Technological
University, 1400 Townsend Dr, Houghton, MI 49931
Melanin is a biological polymer of great interest to the scientific community.
It is believed to play a role in the development of melanoma and Parkinson's
disease, and its semiconducting properties make it a candidate for a variety of
technological applications. While melanin is a substance of great importance,
surprisingly little is known about its polymerization pathway and structure. The
goal of this research is to compare energy dissipation properties of melanin
samples prepared using a variety of techniques. The melanin samples were
characterized using FTIR and studied using femtosecond infrared pump-probe
spectroscopy. The pump-probe results allow for comparison of the samples'
efficiency at dissipating energy. These results will indicate the extent to
which different preparative techniques produce melanin polymers with similar
structural characteristics.
Undergraduate Research Poster Session: Physical Chemistry
2:00 PM-4:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A,
Poster
Division of Chemical Education
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
------------------------------------------------------------
33. Photochemical investigations of diiron model complexes containing the
[Fe2O(O2CR)2]2+ core
INOR 718
Jaired Tate, jaired_tate@yahoo.com, Maurice D. Edington, maurice.edington@famu.edu,
and Edith N. Onyeozili. Department of Chemistry, Florida A&M University, 219
Jones Hall, Tallahassee, FL 32307
Diiron-oxo model complexes have garnered much attention in recent years due to
their structural similarity to a wide array of diiron proteins. Our research
focuses on gaining a comprehensive understanding of how a protein's function is
mediated by active-site protein and solvent interactions; thus, studies on
diiron model complexes provide a chance to study bimetallic centers in the
absence of the surrounding protein. We have synthesized a series of model
complexes containing a core Fe-O-Fe structure in an effort to elucidate key
structural components that modulate dioxygen reactivity in these iron centers.
Various optical spectroroscopic methods (i.e., photoacoustic calorimetry, UV_Vis
absorption and femtosecond transient absorption spectroscopy) were employed to
characterize the electronic structure and excited state characteristics of these
complexes, as well as the dioxygen transport protein hemerythrin, which contains
a diiron center in its active site. Results from the studies on these model
complexes will be presented here.
Spectroscopy of Inorganic Systems
7:00 PM-9:00 PM, Tuesday, April 8, 2008 Morial Convention Center -- Hall A,
Poster
Division of Inorganic Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-------------------------------------------------------------
34. Photochemical investigations of diiron model complexes containing the
[Fe2O(O2CR)2]2+ core
INOR 718
Jaired Tate, jaired_tate@yahoo.com, Maurice D. Edington, maurice.edington@famu.edu,
and Edith N. Onyeozili. Department of Chemistry, Florida A&M University, 219
Jones Hall, Tallahassee, FL 32307
Diiron-oxo model complexes have garnered much attention in recent years due to
their structural similarity to a wide array of diiron proteins. Our research
focuses on gaining a comprehensive understanding of how a protein's function is
mediated by active-site protein and solvent interactions; thus, studies on
diiron model complexes provide a chance to study bimetallic centers in the
absence of the surrounding protein. We have synthesized a series of model
complexes containing a core Fe-O-Fe structure in an effort to elucidate key
structural components that modulate dioxygen reactivity in these iron centers.
Various optical spectroroscopic methods (i.e., photoacoustic calorimetry, UV_Vis
absorption and femtosecond transient absorption spectroscopy) were employed to
characterize the electronic structure and excited state characteristics of these
complexes, as well as the dioxygen transport protein hemerythrin, which contains
a diiron center in its active site. Results from the studies on these model
complexes will be presented here.
Spectroscopy of Inorganic Systems
7:00 PM-9:00 PM, Tuesday, April 8, 2008 Morial Convention Center -- Hall A,
Poster
Division of Inorganic Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
---------------------------------------------------------------
35. 1,2,3,4,5-Pentamethyl-cyclopentadiene dynamics probed by photoionization
PHYS 343
Fedor Rudakov, fedor_rudakov@brown.edu and Peter M. Weber, peter_weber@brown.edu.
Department of Chemistry, Brown University, 324 Brook St, Providence, RI 02912
1,2,3,4,5-pentamethyl-cyclopentadiene has, upon excitation of the 1B2 state at
4.65 eV, an ultrafast curve crossing dynamics that returns the molecule to the
ground state via the 2A1 state. Using time-resolved mass spectrometry and
photoelectron spectroscopy we observed the 1,2,3,4,5-pentamethyl-cyclopentadiene
relaxation and obtained time constants of 182(32) fs and 60(26) fs,
respectively, for the curve crossings. Upon reaching the ground state surface,
the molecule has ample energy to form isomers. Our experiments show
conclusively, however, that no measurable structural changes take place on a
femtosecond or picosecond timescale.
PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A,
Poster
Division of Physical Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-----------------------------------------------------------------
36. Static and time resolved vibrational sum frequency spectroscopy studies of
membrane bound water
COLL 122
R. Kramer Campen, campen@amolf.nl, Avishek Ghosh, ghosh@amolf.nl, Maria Sovago,
and Mischa Bonn, bonn@amolf.nl. Department of Femtophysics, FOM Institute for
Atomic and Molecular Physics [AMOLF], 407 Kruislaan, 1098 SJ Amsterdam,
Netherlands
Much experimental and theoretical work suggests that water participates actively
in determining membrane structure. Elucidating the role of membrane associated
water requires understanding its hydrogen bonding, which is reflected in the
‘bonded-OH' portion of static vibrational sum frequency generation (VSFG)
spectrum of lipid monolayers overlaying water. Such VSFG spectra differ for
different lipid monolayers but understanding the corresponding structural
differences is difficult for two reasons: the OH stretch spectrum is split by
both intra- and intermolecular mode coupling and water structure evolves much
more rapidly than the measurement. We address the former by taking the VSFG
spectrum of the bonded OD region at the membrane/water interface, using a
variety of lipids and trace HOD in H2O, and the latter by application of the
newly developed femtosecond time resolved SFG to the same model membrane
systems. Our results suggest that water chemical heterogeneity differs between
lipids in a chemically unintuitive manner.
Structure, Property, and Function of Cell Membranes and Membrane Related
Biomolecules
2:00 PM-5:20 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 229, Oral
Division of Colloid & Surface Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
------------------------------------------------------------
37 .Investigating semiconductor-photosensitizers using N3 dye analogs
INOR 352
Sheri Lense, slense@emory.edu, Dave Stockwell, dstockw@emory.edu, Tianquan Lian,
tlian@emory.edu, and Cora E. MacBeth, cora.macbeth@emory.edu. Department of
Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322
The N3 dye has been one of the most effective and widely-used dyes for
dye-sensitized solar cells. It consists of a ruthenium(II) center ligated by two
thiocyanates and two 4,4'-dicarboxylic-2,2'-bipyridines. The carboxylic acid
groups tether the dye to the TiO2 semiconducting nanoparticles. There is much to
be learned about the role of ese tethering groups in facilitating electron
transfer between the dye and semiconductor. In order to learn more about this
process, analogues to the N3 dye with various spacing groups inserted between
the bipyridyl groups and carbonyl have been synthesized. The synthesis and
characterization of these dyes using 1H and 13C NMR, infrared and
ultraviolet-visible spectroscopy, as well as mass spectrometry and
electrochemistry, will be reported. Initial studies concerning electron transfer
dynamics of these dyes adsorbed onto TiO2 films using femtosecond infrared
spectroscopy will also be described. These studies will examine the effects of
adding alkyl bridges of increasing length on electron transfer between the dye
and semiconductor
Nanoscience - Characterization and Applications
7:00 PM-9:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Hall A,
Poster
Division of Inorganic Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
----------------------------------------------
38. Electron transfer dynamics at the ZnO (10-10) surface
COLL 129
William A. Tisdale, tisdale@cems.umn.edu1, Matthias Muntwiler2, David J. Norris,
dnorris@umn.edu1, Eray Aydil, aydil@umn.edu1, and Xiaoyang Zhu, zhu@umn.edu2.
(1) Department of Chemical Engineering and Materials Science, University of
Minnesota, 151 Amundson Hall, 421 Washington Ave SE, Minneapolis, MN 55455, (2)
Department of Chemistry, University of Minnesota, 207 Pleasant St SE,
Minneapolis, MN 55455
Recently, ZnO nanoparticle films and nanowire arrays have been used in lieu of
TiO2 in dye- and quantum dot-sensitized solar cells and in hybrid
organic/inorganic bulk heterojunction photovoltaic devices. The nonpolar (10-10)
surface is the lowest-energy ZnO surface and constitutes the side facets of ZnO
nanowires and much of the surface area of sintered ZnO nanoparticle films.
Consequently, the majority of charge separation and recombination events in
these devices occur at the (10-10) or equivalent surfaces. We are using
time-resolved photoemission and surface nonlinear optical spectroscopies to
study electron transfer dynamics at this important surface. On the clean (10-10)
surface we find a continuum of defect-derived surface states extending into the
band gap below the conduction band edge which may play an important role in
electron transfer across this surface and in electron transport in devices
featuring ZnO photoanodes. Additionally, we observe ultrafast sub-20 femtosecond
cooling of hot electrons within the ZnO conduction band, suggesting that hot
carrier transport may not be feasible in this material.
Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to
Nanomaterials
2:00 PM-6:00 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 226, Oral
Division of Colloid & Surface Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
-------------------------------------------------
39. Effect of morphology in KNb6O17 nanosheets
and nanoscrolls on photocatalytic H2 evolution from water
PETR 30
Michael Sarahan, mcsarahan@ucdavis.edu1, Elizabeth C Carroll, eccarroll@ucdavis.edu1,
Nigel D Browning2, Delmar S. Larsen,
dlarsen@ucdavis.edu1, and Frank E. Osterloh, fosterloh@ucdavis.edu1. (1)
Department of Chemistry, University of California, Davis, One Shields Avenue,
Davis, CA 95616, (2) Department of Chemical Engineering and Materials Science,
University of California Davis, One Shields Ave., Davis, CA 95616
Layered K4Nb6O17 has a bandgap of 3.5 eV and is a known catalyst for water
splitting under UV light. Exchange of the K+ ions with propylammonium or
tetrabutylammonium in water leads to nanosheets or nanoscrolls, respectively.
The nanoscrolls are composed of a single niobate layer, whereas the sheets
consist of two layers held electrostatically together by potassium ions. Under
UV light both materials catalyze H2 evolution from water. Chemical deposition of
Pt particles on the niobates increases the activity to up to 350 micromol/h (175
mg of catalyst). Similarities and differences in the two catalysts are discussed
using data from TEM, HRTEM, UV/vis, fluorescence, IR, and femtosecond absorption
spectroscopy.
2nd Symposium on Hydrogen from Renewable Sources and Refinery Applications
1:00 PM-5:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 222, Oral
Division of Petroleum Chemistry
The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008
Come to San Diego next summer! Attend one of our training workshops in San Diego, California
during summer 2011 Del Mar Photonics has presented training workshops for customers and potential customers in the past 3 years. Our workshops cover scientific basics, technical details and provide generous time for hands-on training. Each workshop is a three-day seminar conducted by professional lecturer from 10am to 4pm. It includes lunch, as well as a training materials. We have also reserved two days for Q&A sessions, one-on-one system integration discussions, social networking, and San Diego sightseeing.
The following training workshops will be offered during this
summer: |
Featured Customer
Trestles LH10-fs/CW laser system at UC Santa Cruz Center of Nanoscale Optofluidics
Del
Mar Photonics offers new
Trestles fs/CW laser system which can be easily
switched from femtosecond mode to CW and back. Having both modes of operation in one system dramatically increase a
number of applications that the laser can be used for, and makes it an ideal
tool for scientific lab involved in multiple research projects. |
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Frequency-stabilized CW single-frequency ring Dye laser DYE-SF-007 pumped by DPSS DMPLH laser installed in the brand new group of Dr. Dajun Wang at the The Chinese University of Hong Kong. DYE-SF-077 features exceptionally narrow generation line width, which amounts to less than 100 kHz. DYE-SF-077 sets new standard for generation line width of commercial lasers. Prior to this model, the narrowest line-width of commercial dye lasers was as broad as 500 kHz - 1 MHz. It is necessary to note that the 100-kHz line-width is achieved in DYE-SF-077 without the use of an acousto-optical modulator, which, as a rule, complicates the design and introduces additional losses. A specially designed ultra-fast PZT is used for efficient suppression of radiation frequency fluctuations in a broad frequency range. DYE-SF-077 will be used in resaerch of Ultracold polar molecules, Bose-Einstein condensate and quantum degenerate Fermi gas and High resolution spectroscopy |
Other News
Optical Society of Southern California meeting at UCSD OSSC 2011-04-27
Nd:YAG laser ordered by the University of Leon, UANL, Mexico
Wedge 50 Multipass Amplifier pumped with a Darwin-527-30-M DPSS Laser
ordered by Hong Kong customer
New
Trestles LH10-fs/CW femtosecond+CW laser ready for delivery to the
University of California Santa Cruz
Trestles femtosecond
Ti:Sapphire laser delivered to North Carolina State
University
Del Mar Photonics sponsor IONS (International OSA Network of Students)
conference IONS-NA-2 in Tucson, Arizona
IONS-NA-2
website
Best talk and best
poster awards at IONS-Moscow 2010 conference sponsored by Del Mar Photonics
Watch Del Mar Photonics
videos!
Del Mar Photonics is now on Twitter!
Del Mar Photonics featured components
Del Mar Photonics continuously expands its components portfolio.
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Solar
Prisms for Concentrating Photovoltaic Systems (CPV) Solar cells made of compound semiconductors such as gallium arsenide are very expensive. Usually very small cells are installed and various means such as mirrors, lenses, prisms, etc..are used to concentrate sunlight on the cells. Concentration photovoltaic technology (CPV) uses the solar radiation with an efficiency of 40%, double that of conventional solar cells Del Mar Photonics design custom Concentrating Photovoltaic Systems (CPV) and supply variety of the optical components for CPV such as solar prisms shown in the picture. |
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Axicon Lens Axicon lens also known as conical lens or rotationally symmetric prism is widely used in different scientific research and application. Axicon can be used to convert a parallel laser beam into a ring, to create a non diffractive Bessel beam or to focus a parallel beam into long focus depth. Del Mar Photonics supplies axicons with cone angles range from 130° to 179.5° for use with virtually any laser radiation. We manufacture and supply axicons made from BK7 glass, fused silica and other materials. download brochure - request a quote |
Rutile (TiO2) coupling
prisms Del Mar Photonics offers optical elements made of high quality synthetically grown Rutile Titanium Dioxide crystals. Rutile’s strong birefringency, wide transmission range and good mechanical properties make it suitable for fabrication of polarizing cubes, prisms and optical isolators. Boules having high optical transmission and homogeneity are grown by proprietary method. Typical boules have 10 - 15 mm in dia. and up to 25 mm length. Optical elements sizes - from 2 x 2 x 1 mm to 12.7 x 12.7 x 12.7 mm. Laser grade polish quality is available for finished elements. So far we the largest elements that we manufactured are 12 x15 x 5 mm, in which optical axis is parallel to 15 mm edge, 5 mm is along beam path, 12 x 15 mm faces polished 20/10 S/D, one wave flatness, parallelism < 3 arc.min. (better specs. available on request). more details - download brochure - request a quote |
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Vacuum viewport Del Mar Photonics offer a range of competitively priced UHV viewports , Conflat, ISO or KF including a variety of coatings to enhance performance. Del Mar Photonics viewports are manufactured using advanced techniques for control of special and critical processes, including 100 percent helium leak testing and x-ray measurements for metallization control. Windows Materials include: Fused silica, Quartz , Sapphire , MgF2, BaF2, CaF2, ZnSe, ZnS, Ge, Si, Pyrex. Standard Viewing diameters from .55" to 1.94 ". Coating - a range of custom coatings can applied - which include - Single QWOT - Broad Band AR - V coatings - ITO - DLC (Diamond like coating) more details - request a quote |
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Hydrogen
Thyratrons are used in
such devices as radars with different power levels, high-power pulsed
technical, electrophysical, medical devices and lasers. Sophisticated
design and high quality ceramic-metal envelope determines long lifetime
and very accurate and reliable operation of hydrogen thyratrons under wide range of environmental
conditions. Applications: - radars - pulsed lasers power supplies - medical apparatus - electrophysical instrumentation Triggered Three-Electrode Spark Gap Switches are ceramic-metal sealed off gas discharge trigatron-type devices with a co-axial trigger electrode. These Gas Discharge Tubes contain no mercury and, due to an advanced design, feature high reliability and a long lifetime being operating under wide range of environmental conditions. Applications: - pulsed installation for processing materials - installations with plasma focus - pulse power supplies for lasers and other pulse equipment - medical apparatus such as lithotriptors and defibrillators - processing systems for petroleum wells |
We are looking forward to hear from you and help you with your optical and crystal components requirements. Need time to think about it? Drop us a line and we'll send you beautiful Del Mar Photonics mug (or two) so you can have a tea party with your colleagues and discuss your potential needs. |
Del Mar Photonics, Inc.
4119 Twilight Ridge
San Diego, CA 92130
tel: (858) 876-3133
fax: (858) 630-2376
Skype: delmarphotonics
sales@dmphotonics.com