MIXED QUANTUM-CLASSICAL STUDIES OF H-2 DISSOCIATION ON METALS - DEPENDENCE UPON MOLECULAR-GEOMETRY AND DIMENSIONALITY

A mixed quantum-classical model is used to compute the probability for dissociation and rotational excitation for H-2, HD, and D2 scattered from a Ni surface. The vibrational coordinate, the polar orientation angle, and the center of mass translation of the molecule normal to the surface are treated quantum mechanically using 3D spectral grid/fast Fourier transform techniques. The remaining degrees of freedom are treated classically. The dissociation probabilities are computed as a function of molecular kinetic energy and compared with those determined in a previous 2D study. An increase in rotational excitation coincides with an increase in dissociation as predicted by a recently developed analytical model. The dependence of the dissociation and rotational excitation probabilities on initial internal molecular state, molecular orientation, and surface impact site are also examined.