Accession Number : ADA118789

Title :   Rotationally Mediated Selective Adsorption as a Probe of Isotropic and Anisotropic Molecule - Surface Interaction Potentials: HD(J)/Ag(111).

Descriptive Note : Interim technical rept.,


Personal Author(s) : Yu,Chien-Fan ; Hogg,Charles S ; Cowin,James P ; Whaley,K Birgitta ; Light,John C

PDF Url : ADA118789

Report Date : Aug 1982

Pagination or Media Count : 44

Abstract : Rotationally mediated selective adsorption scattering resonances are used to make an experimental and theoretical study of the laterally averaged interaction potential between HD and a weakly corrugated system, Ag(111). The experimentally observed resonances determine the vibrational levels of the HD/Ag(111) physisorption potential as a function of bound rotational state. These vibrational levels show J-dependent shifts due to the orientational anisotropy of the potential. Exact quantum scattering calculations using a full laterally averaged potential of the form V sub o(z,0) = v sub o (z) (1 + beta P sub 2 (cos theta)) have been carried out to obtain rotationally inelastic transition probabilities. Experimental and theoretical resonance energies are compared for two forms of v sub o(z), a Morse and a variable exponent potential, as a function of Beta, and are found to be very close to the first order perturbed energies of a free rotor in bound states of v sub o(z). Both potential forms give equally good fits to the data, yielding an optimum value of the asymmetry parameter, Beta approx. -0.05. The determination of Beta is relatively insensitive to small changes in the v sub o(z) well depth. (Author)

Descriptors :   *Molecular rotation, *Absorption, *Probes, *Inelastic scattering, Anisotropy, Asymmetry, Interactions, Perturbations, Energy, Transitions, Probability, Quantum statistics

Subject Categories : Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE