Wavepacket approach to triatomic photodissociation and molecule-surface reactive scattering.

摘要

The theoretical and computational details of the wavepacket approach to molecular dynamics are presented. Several novel methods for wavepacket propagation which maximize computational efficiency are highlighted. Wavepacket propagation in the Interaction Representation is utilized to eliminate oscillations in the wavepacket and provide a tremendous savings in the number of grid points. This method can be applied together with shifts in both momentum and coordinate space to provide additional savings. The Interaction Representation is also used to transform a non-hermitian Hamiltonian to a Hermitian Hamiltonian. Two applications of the wavepacket approach are presented: photodissociation of ICN and NO{dollar}sp{lcub}+{rcub}{dollar}/GaAs(110) reactive scattering. The calculation of ICN photodissociation in the A continuum is performed using the ab initio potential surfaces of Morokuma and coworkers. The calculated absorption spectrum, {dollar}beta{dollar} parameters, the I/I{dollar}*{dollar} branching ratio and the rotational product distribution are in good agreement with experiment. In the study of the NO{dollar}sp{lcub}+{rcub}{dollar} molecular ion/surface reactive scattering, a novel procedure for treating the coupling of a molecular state with a band of substrate electronic states is combined with a mixed classical-quantal treatment of the nuclear motion. The results suggest that electron transfer and collision induced dissociation (CID) cooperate and form a vibrational coherence where the initial vibrational state strongly influences the dissociation dynamics.