NONADIABATIC PHASE-MATRIX METHOD FOR VIBRATIONAL-EXCITATION AND DISSOCIATIVE ATTACHMENT IN ELECTRON-MOLECULE SCATTERING

The R-matrix theory of vibronic processes in electron-molecule scatter ing is developed from a generalized variational formalism, valid for a ny enclosed system of interacting particles with different mass parame ters. The question of choice of variational basis functions is discuss ed, examining practical reasons for using basis functions that do not have specified boundary values or normal gradients on the boundary sur face of the enclosed volume. A nonadiabatic theory is derived in which the vibronic R matrix, including channels describing dissociation pro cesses, is deduced from the fixed-nuclei electronic R matrix, given as a function of electronic energy and internuclear distance.