| oth classical and mixed quantum-classical approaches have been used to study the non-thermal desorption of CO from a variety of model surfaces to which it is weakly adsorbed. In addition to three degrees of freedom for the CO adsorbate (bond stretching, physisorption, libration) which are treated quantum mechanically in the mixed method, a significant number of lattice degrees of freedom have been included using the generalized Langevin approximation. In the mixed method, two sets of equations for the quantum and classical subsystems (coupled via the Ehrenfest theorem) are solved self-consistently using the discrete variable represenation method for the propagation of the quantum wave function. Non-thermal amounts of energy have been put into both the CO stretching and librational modes at t = 0. We find that for initial values of the stretching quantum number ;An indirect mechanism for populating rapidly desorbing, highly excited levels of surface CO, based on intermolecular... |
