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Title: Capturing Transient Electronic and Molecular Structures in Liquids by Picosecond X-Ray Absorption Spectroscopy

Abstract

We describe an advanced setup for time-resolved x-ray absorption fine structure (XAFS) Spectroscopy with picosecond temporal resolution. It combines an intense femtosecond laser source synchronized to the x-ray pulses delivered into the microXAS beamline of the Swiss Light Source (SLS). The setup is applied to measure the short-lived high-spin geometric structure of photoexcited aqueous Fe(bpy)3 at room temperature.

Authors:
 [1];  [2]; ; ; ; ; ;  [1]; ; ;  [3];  [4]
  1. Laboratoire de Spectroscopie Ultrarapide (LSU), Ecole Polytechnique Federale de Lausanne (EPFL), BSP, CH-1015 Lausanne (Switzerland)
  2. (Switzerland)
  3. Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI (Switzerland)
  4. Departement de Chimie Physique, Universite de Geneve, CH-1121 Geneva (Switzerland)
Publication Date:
OSTI Identifier:
21054620
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 882; Journal Issue: 1; Conference: XAFS13: 13. international conference on X-ray absorption fine structure, Stanford, CA (United States), 9-14 Jul 2006; Other Information: DOI: 10.1063/1.2644425; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTRA; ABSORPTION SPECTROSCOPY; FINE STRUCTURE; IRON COMPOUNDS; LIQUIDS; MOLECULAR STRUCTURE; ORGANIC COMPOUNDS; PULSES; SPIN; SWISS LIGHT SOURCE; TIME RESOLUTION; TRANSIENTS; TRANSITION ELEMENTS; X-RAY SPECTRA; X-RAY SPECTROSCOPY

Citation Formats

Gawelda, W., Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Pham, V. T., El Nahhas, A., Kaiser, M., Zaushitsyn, Y., Bressler, C., Chergui, M., Johnson, S. L., Grolimund, D., Abela, R., and Hauser, A.. Capturing Transient Electronic and Molecular Structures in Liquids by Picosecond X-Ray Absorption Spectroscopy. United States: N. p., 2007. Web. doi:10.1063/1.2644425.
Gawelda, W., Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Pham, V. T., El Nahhas, A., Kaiser, M., Zaushitsyn, Y., Bressler, C., Chergui, M., Johnson, S. L., Grolimund, D., Abela, R., & Hauser, A.. Capturing Transient Electronic and Molecular Structures in Liquids by Picosecond X-Ray Absorption Spectroscopy. United States. doi:10.1063/1.2644425.
Gawelda, W., Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Pham, V. T., El Nahhas, A., Kaiser, M., Zaushitsyn, Y., Bressler, C., Chergui, M., Johnson, S. L., Grolimund, D., Abela, R., and Hauser, A.. 2007. "Capturing Transient Electronic and Molecular Structures in Liquids by Picosecond X-Ray Absorption Spectroscopy". United States. doi:10.1063/1.2644425.
@article{osti_21054620,
title = {Capturing Transient Electronic and Molecular Structures in Liquids by Picosecond X-Ray Absorption Spectroscopy},
author = {Gawelda, W. and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI and Pham, V. T. and El Nahhas, A. and Kaiser, M. and Zaushitsyn, Y. and Bressler, C. and Chergui, M. and Johnson, S. L. and Grolimund, D. and Abela, R. and Hauser, A.},
abstractNote = {We describe an advanced setup for time-resolved x-ray absorption fine structure (XAFS) Spectroscopy with picosecond temporal resolution. It combines an intense femtosecond laser source synchronized to the x-ray pulses delivered into the microXAS beamline of the Swiss Light Source (SLS). The setup is applied to measure the short-lived high-spin geometric structure of photoexcited aqueous Fe(bpy)3 at room temperature.},
doi = {10.1063/1.2644425},
journal = {AIP Conference Proceedings},
number = 1,
volume = 882,
place = {United States},
year = 2007,
month = 2
}
  • Transient molecular structures along chemical reaction pathways are important for predicting molecular reactivity, understanding reaction mechanisms, as well as controlling reaction pathways. During the past decade, X-ray transient absorption spectroscopy (XTA, or LITR-XAS, laser-initiated X-ray absorption spectroscopy), analogous to the commonly used optical transient absorption spectroscopy, has been developed. XTA uses a laser pulse to trigger a fundamental chemical process, and an X-ray pulse(s) to probe transient structures as a function of the time delay between the pump and probe pulses. Using X-ray pulses with high photon flux from synchrotron sources, transient electronic and molecular structures of metal complexes havemore » been studied in disordered media from homogeneous solutions to heterogeneous solution-solid interfaces. Several examples from the studies at the Advanced Photon Source in Argonne National Laboratory are summarized, including excited-state metalloporphyrins, metal-to-ligand charge transfer (MLCT) states of transition metal complexes, and charge transfer states of metal complexes at the interface with semiconductor nanoparticles. Recent developments of the method are briefly described followed by a future prospective of XTA. It is envisioned that concurrent developments in X-ray free-electron lasers and synchrotron X-ray facilities as well as other table-top laser-driven femtosecond X-ray sources will make many breakthroughs and realise dreams of visualizing molecular movies and snapshots, which ultimately enable chemical reaction pathways to be controlled.« less
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  • Transient absorption spectra have been recorded in the range 350-750 nm in solution at room temperature for poly(phenylmethylsilane). A transient absorption band at 450 nm resembles that of pHMeSi, and a band at 370 nm is another product. Both rise time and decay times of the transients were determined. Room temperature hole burning of the absorption spectrum is reported.
  • Ultraviolet multiphoton excitation with a picosecond laser pulse at the wavelength of no appreciable ground-state absorption has been used to excite benzene and alkylbenzenes homogeneously in the neat liquid state and to investigate their photophysical and photochemical primary processes by picosecond time-resolved transient absorption spectral measurements. The excimer formation processes in neat liquid benzenes excited by two-photon absorption of the 355-nm picosecond pulse from a Nd/sup 3 -/:YAG laser have been confirmed to proceed via ionization and recombination processes, and the lifetime of the ionized (ion pair) state has been determined to be 10-20 ps in neat benzene. 26 references,more » 4 figures, 4 tables.« less