Semiclassical investigation of electron transfer reactions in H+2/H2, H+2/D2, D+2/H2, and D+2/D2 collisions

The semiclassical energy conserving trajectory method has been used to determine state-to-state cross sections for the electron transfer reactions, H+2/H2, and isotopic variants. Accurate diabatic interactions were utilized. Calculations were performed for several reactant orientations, initial ion vibrational states, and relative kinetic energies. The state-to-state cross sections are used to test three simple models: an exponential gap correlation procedure, a Franck--Condon exponential gap correlation procedure, and a two-state calculational method. All three are found to be inadequate, and the failure is ascribed to the strongly coupled multistate nature of symmetric electron transfer reactions. We predict the variation of relative total electron transfer cross section with initial ion vibrational state for all four systems. The D+2/H2 system exhibits very unusual behavior at low kinetic energies. D+2/H2, and D+2/D2