Semiclassical wave packet model for the investigation of elastic and inelastic gas--surface scattering

Journal Article · Fri Oct 15 04:00:00 EDT 1982 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.444348· OSTI ID:6864629

Agrawal, P M; Raff, L M

A semiclassical wave packet model that permits simultaneous study of surface diffraction, Debye--Waller effects, and inelastic energy transfer processes at the gas--surface interface is presented. The incident atomic beam is represented by a quantum mechanical wave packet whose momentum-space probability density corresponds to that employed in the molecular-beam experiments being simulated. A semiclassical forced-oscillator-type approximation couples the surface motion to that of the wave packet through a time-varying potential obtained from a solution of Hamilton's equations of motion for the lattice. Explicit integration procedures are used to evolve the wave packet through this time-varying field. The average final kinetic energy of the beam, the angular distributions and diffraction patterns, Debye--Waller broadening effects, and the surface phonon spectrum are obtained from the scattered wave packet and its Fourier transform. The model has been applied to the case of an atomic hydrogen beam having a square distribution of incident momenta impinging upon a simple two-dimensional lattice. The results yield diffraction patterns that correlate with the known grating of the lattice. The average final kinetic energy of the beam is found to vary linearly with incident energy and with surface temperature in accord with the results of recent molecular beam experiments, and a surface phonon spectrum that exhibits one-, two-, and three-phonon processes is obtained.

• Research Organization: Department of Physics, Government College, Ajmer (Rajasthan), India
• OSTI ID: 6864629
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 77:8; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640301* -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOM COLLISIONS
COLLISIONS
ELASTIC SCATTERING
FLUIDS
GASES
INELASTIC SCATTERING
SCATTERING
SEMICLASSICAL APPROXIMATION
SURFACES