A REDUCED DIMENSION QUANTUM WAVE PACKET STUDY OF PHOTODISSOCIATION DYNAMICS OF DIATOMIC-MOLECULES ON SURFACES

Photodissociation dynamics of a model diatomic molecule adsorbed on an MgO (001) surface is studied using Hamiltonians having two actively treated mathematical dimensions. Dissociation/desorption at three orientations, i.e., theta = 0-degrees, 90-degrees, and 180-degrees (where theta is the angle between the molecular axis and the surface normal), is investigated. The dynamics is represented by quantum wave packets which provide detailed information about the time evolution of the system. Trapping of one or two dissociated atoms is observed and the trapped vibrational state distributions are calculated. When the light atom is between the surface and the heavy one, oscillation of this atom between the two heavy partners can cause energy transfer to the outer atom. This results in a broadened and upward shifted translational energy distribution of the desorbed heavy atom, compared to the gas phase result.