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University of Virginia
Department of Chemistry
409 McCormick Road
P.O. Box 400319
Charlottesville, VA 22904-4319
Phone: (434)924-3639/3654
Fax: (434)924-3966

email : Prof. Ian Harrison

 

  Ultrafast Photchemistry Lab.
Graduate Students: Leticia Valadez / Greg Cushing
 

 

 

 

 

Fig 1. Schematic of UHV Chamber in Ultrafast Photochemistry Lab.
 
Research Overview

A dream of surface chemists is to directly interrogate the reaction dynamics of catalysis using ultrafast lasers in stroboscopic experiments. Unfortunately, the time evolution of a reacting surface system precludes extended signal averaging under most circumstances. Nevertheless, impressive progress in monitoring electronic and nuclear dynamics at surfaces has been made in recent years (see for example Martin Wolf's website).

So far, in surface science, the short pulse duration and high intensiy of ultrafast lasers have proven particularly useful to: (a) facilitate surface non-linear optical spectroscopies such as second harmonic generation, sum frequency generation, and two-photon photoemission; and (b) transiently excite surface electrons to high temperatures (ca. 10,000 K) such that electron transfer chemistry to high lying adsorbate affinity levels becomes facile. This can be done without melting the sample because the relatively low heat capacity of the electrons leads to an optically-driven transient excursion of the electron temperature which couples only slowly to the phonons, whose temperature lags far behind.

At Virginia, the recently completed ultrahigh vacuum system outlined below is well suited for studies of surface photochemistry, non-linear optics and two-photon photoemission. In situ diagnostic techniques include x-ray photoelectron spectroscopy, Auger electron spectroscopy, and thermal programmed desorption spectroscopy. The laser system comprises part of the Center for Atomic, Molecular and Optical Science's (CAMOS) Ultrafast Laser Facility. Our current experiments focus on the photochemistry and catalytic activation of small molecules adsorbed on transition metal surfaces doped with alkali metal promoters.

 
This material is based upon work supported by the National Science Foundation, the Department of Energy, and the American Chemical Society's Petroleum Research Foundation.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF, DOE, or ACS PRF.
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