Accession Number : ADA311227

Title :   Dynamics of Gas-Surface Interactions.

Descriptive Note : Final technical rept. 1 Nov 92-30 Apr 96,

Corporate Author : CHICAGO UNIV IL

Personal Author(s) : Sibener, Steven J.

PDF Url : ADA311227

Report Date : 15 JUN 1996

Pagination or Media Count : 59

Abstract : A wide variety of gas-surface-and electron-surface scattering experiments, supported by lattice dynamics, molecular dynamics, and scattering calculations were carried out under the auspices of this grant. These studies were motivated by a desire to understand and control surface reactions, such as surface oxidation, the technological need to characterize the physical properties of thin films and surfaces, and the desire to understand how energy and momentum are exchanged at an interface subjected to gas-surface or electron-surface collisions. Experiments involved clean, alloyed, oxidized, and stepped metallic interfaces. Surface phonon dispersion relations, and hence surface forcefields, for clean and adsorbate covered systems were determined using inelastic atom and electron scattering, providing a microscopic basis for assessing structural stability at interfaces. Major advances occurred in our understanding of the forces which are present at atomic-level steps, as well as in the area of metallic oxidation, including oxide nucleation. Synergistic effects involving electrons were shown to significantly modify metallic oxidation kinetics. Other projects dealt with alloy surface structure and stability, adsorbate negative ion resonances, dipole interactions of adsorbates, spectroscopy of frustrated low energy adsorbate vibrational modes, molecular dynamics simulations of surface vibrational dynamics, and anharmonicity in surface potentials. p1

Descriptors :   *DYNAMICS, *GAS SURFACE INTERACTIONS, SIMULATION, METALS, SCATTERING, STABILITY, VIBRATION, COMPUTATIONS, SPECTROSCOPY, REACTION KINETICS, INTERACTIONS, INTERFACES, PHYSICAL PROPERTIES, STRUCTURAL PROPERTIES, ELECTRON SCATTERING, ELASTIC PROPERTIES, THIN FILMS, ATOMS, NUCLEATION, ALLOYS, SURFACE PROPERTIES, OXIDATION, OXIDES, DIPOLES, SURFACE REACTIONS, LATTICE DYNAMICS, PHONONS, MOLECULAR PROPERTIES, MOMENTUM, SYNERGISM, COLLISIONS, CONTROL SURFACES, ADSORBATES, DISPERSION RELATIONS.

Subject Categories : Physical Chemistry
      Inorganic Chemistry
      Properties of Metals and Alloys
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE