Physical Chemistry, Gas-Surface Dynamics, Photochemistry
Lab: Molecular Beam Facility
P.O. Box 173400
Bozeman, MT 59717
Ph: (406) 994-5394
Fax: (406) 994-6011
B.S., University of Illinois at Urbana-Champaign, 1980; Ph.D., University of California at Berkeley, 1986; Postdoctoral, University of Illinois at Urbana-Champaign, 1986-88; Postdoctoral, University of Zurich, Switzerland, 1988-89
Awards and Professional Activities:
Aurora Illinois Foundation Scholarship, 1976-80; University of Illinois Summer Fellowship, 1979; NASA Monetary Award for a Technological Contribution, 1995; MSU Alumni/Bozeman Chamber of Commerce Excellence Award, 1996.
Molecular beam-surface scattering techniques are used to understand in detail the interactions between fast atoms or molecules and surfaces. At collision energies of many electron volts, non-equilibrium interactions become important. Such interactions may control the outcome of processes such as etching, surface-chemistry modification, and materials degradation on spacecraft. Our research goals are to understand fundamental gas-surface interactions in the regime of hyperthermal collision energies and to apply the knowledge gained to the solution of real-world problems.
In addition to beam-surface experiments, we have a second research component aimed at understanding the photochemical decomposition pathways that are important in stratospheric ozone depletion. Chlorine nitrate (ClONO2), for example, is an important reservoir species for chlorine and NOx in the stratosphere. By conducting a UV photodissociation study on ClONO2 in a molecular beam and detecting the photofragments with the rotatable mass spectrometer, we discovered that two dissociation channels occur with comparable probabilities: ClO + NO2 and Cl + NO3. The first of these dissociation pathways was previously believed to be unimportant. More recently, we completed a study of the UV photodissociation of the chlorine monoxide dimer, ClOOCl. Our experiments have demonstrated that photoexcitation of ClOOCl leads to dissociation via multiple pathways, producing ClO + ClO and 2Cl + O2. These results substantially confirm the long-held belief that ClOOCl photolysis is important in the catalytic destruction of ozone over the polar regions.
Chemistry & Biochemistry
103 Chemistry and Biochemistry Building
PO Box 173400
Bozeman, MT 59717