Scattering of Atoms and Molecules by Surfaces

Clemson University, Clemson SC

Investigators

Abstract

0089503 Manson This is award to develop and extend the theory of surface scattering of atoms and small molecules. The thrust of the work in this proposal is toward developing a theory in the semiclassical and classical regime that includes the exchange of energy with the lattice vibrations of the surface, the rotational excitation of the molecule, and the excitation of internal vibrational modes of the molecule. The resulting theory will provide information on scattering, sticking, and desorption of molecular projectiles and will help in understanding the dynamics that lead to elementary chemical reactions on the surface. The focus of this work will be to determine the influence of more realistic interaction potentials in atom scattering and to extend the approach to develop a fully self-consistent theory of molecular scattering with surfaces. Extensive numerical calculations will be performed to compare the theory with experiments. Calculations for specific systems include: state-to-state scattered distributions and sticking coefficients of small molecules like CH4 and C2H2 from LiF(001) surfaces, metal substrates, and adsorbate covered surfaces; heavy rare gases scattering from liquid surfaces with the aim of exploring the ability of such experiments to give information on the surface composition of liquid metal alloy mixtures; photodesorption probabilities of alkali atoms and small molecules such as NO with an aim to extract information on the effects of temperature through lattice vibrations. %%% This is an award involving participation of graduate students and undergraduate students to develop a quantitative theory of atomic and molecular scattering from surfaces. The application of such a theory will enable extraction from experiments, of basic physical information on the interaction of specific atoms and molecules with surfaces, on defects and adsorbates on surfaces, and on the surface itself. This information is potentially useful for a wide variety of applications including the construction and characterization of robust nanoscale structures on surfaces. ***