Wayne P Hess
Associate Director - CS&D, Fundamental and Computational Sciences Directorate, Chemical and Material Sciences Division, Chemical Structure and DynamicsCurrent Activities and Projects
Laser desorption and laser-solid interactions, excited state processes in solids, photoemission electron microscopy
Research Interests
The elucidation of physical and dynamic processes of electronically excited solids is an essential requirement in understanding laser-solid interactions and the radiation chemistry of condensed matter. Photo-stimulated desorption of particles and molecules provides a direct window into many of these important processes and is particularly indicative of surface electronic structure and dynamics. Time-resolved optical spectroscopic techniques can provide complementary information on excited state processes in the bulk material. Indeed, bulk dynamical processes often lead directly to particle desorption or creation of precursor states or defects that greatly influence subsequent chemistry. Excited state chemistry in solids is inherently complicated and greater understanding usually requires joint theoretical development. We design our experiments in close collaboration with an internationally recognized solid-state theory group and use the results of ab initio calculations to provide the basic hypotheses for our research. The experiments are designed to test theoretical predictions. We have developed laser techniques to study solid-state chemistry using tunable femtosecond and nanosecond lasers to excite wide-gap materials under highly controlled conditions. We monitor particle emission using quantum-state specific laser ionization and probe surface chemical transformations using surface sensitive techniques such as x-ray photoelectron spectroscopy (XPS). We are able to demonstrate cases of laser control of reactions within solids and at surfaces by appropriate selection of photon energy or by inducing reactions using pulse sequences. Ultimately, our efforts are directed toward providing the radiation and analytical chemistry research needs required by the DOE environmental restoration mission.
Past Experience
- Chief Scientist, Pacific Northwest Natioanl Laboratory, Richland, WA 99352.
- 1988-1990 - Postdoctoral Research Associate, Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551.
- 1983-1988 - Graduate Research and Teaching Assistant, Dept. of Chemistry, University of Colorado, Boulder, CO, 80309.
Education
- Ph.D. Physical Chemistry University of Colorado, Boulder, CO, January, 1988.
- M.S. Chemical Physics University of Oregon, Eugene, OR May 1983.
- B.A. Chemistry University of Colorado, Boulder, CO May 1981.
Awards, Honors, & Appointments
- Co-Chairman Eighth International Conference on Laser Ablation (COLA 05)
- Vice-chair Gordon Research Conference "Laser Interactions with Materials
