Accession Number : ADA304289

Title :   Gas-Surface Interactions Near Dissociation Threshold.

Descriptive Note : Final rept. 1992-1995,

Corporate Author : UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF CHEMISTRY

Personal Author(s) : Reisler, Hanna ; Wittig, Curt

PDF Url : ADA304289

Report Date : FEB 1996

Pagination or Media Count : 6

Abstract : Two aspects of molecular decomposition on MgO(100) surfaces were explored. Nitrogen dioxide entrained in a molecular beam was photoexcited and directed at a crystal surface. Following collision, it had enough internal plus translational energy to undergo dissociation. The NO products, which were detected with state and angular resolution, were scattered preferentially in the specular direction and their internal energies were analyzed The results showed that the collisional dissociation was rather efficient when the molecules possessed internal energies approaching dissociation energy The photochemistry of CINO was examined on MgO and compared with the analogous gaseous phase photodissociation; a large, qualitative difference was observed. Defect-laden and relatively defect-free MgO(100) surfaces were used. Gas phase 355 nm photolysis yielded NO with a rotational distribution peaked at high rotational levels, whereas adsorbed CINO always yielded cold NO. The results suggested that CINO aggregated on the surface in a way that affects photon-induced processes. The gas-phase photodissociation dynamics of FNO and methyl nitrite were examined as candidates for comparisons with surface photolysis. jg p1

Descriptors :   *GASES, *SURFACES, *DISSOCIATION, PHOTOCHEMICAL REACTIONS, PHOTODISSOCIATION, CHEMICAL DISSOCIATION, METHYL RADICALS, PHOTOLYSIS, DISTRIBUTION, INTERACTIONS, MOLECULES, ADSORPTION, INSULATION, EXCITATION, ENERGY, RESOLUTION, CRYSTALS, MOLECULAR BEAMS, INTERNAL, FLUORINE, PHOTONS, ROTATION, DECOMPOSITION, COLLISIONS, ANGULAR MOTION, CHLORINE COMPOUNDS, SPECULAR REFLECTION, DEFECT ANALYSIS, MAGNESIUM OXIDES, NITROGEN DIOXIDE, NITRITES.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Radiation and Nuclear Chemistry
      Crystallography
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE