DYNAMICS OF SURFACE-ALIGNED PHOTOCHEMISTRY (THEORY) .2. LOCALIZED H-ATOM SCATTERING IN THE HBR(AD)/LIF(001)+H-NU SYSTEM

The angular and energy distributions of 1.1 and 2.6 eV H-atom scattering from a LiF(001) surface are compared for two different sources of hot H-atoms (1) localized H-atoms produced by the photolysis of HBr molecules adsorbed on the LiF surface; and (2) H-atoms from a beam at the same energy and angle of approach to the LiF surface as in (1). These distributions are the results of classical stochastic trajectories carried out on a 7 X 7 slab of LiF(001). The calculated angular distributions are compared with experimental distributions [E. B. D. Bourdon et al., J. Chem. Phys. 95, 1361 (1991)]. The computed effects of changing H-atom energy and surface temperature are also reported; localized scattering becomes increasingly nonspecular at lower photon energies, and broader at higher surface temperatures.