A coupled channels approach to Penning ionization of Ar by He*(1s2s,3S)

A discretization procedure has been applied to the continuum of electronic states encountered in Penning ionization (PI) and associative ionization (AI) of an atom B by an excited (metastable) atom A*, where A*+B→A+B++e- (PI) and A*+B→AB++e- (AI). Within the context of discretization, a procedure has been introduced which treats the collision dynamics of PI and AI processes in terms of a small number of two-state coupled equations, each associated with a particular amount of kinetic energy epsilon removed by the emitted electron. Application has been made to PI of Ar by He* (1s2s,3S). Calculated results of partial ionization cross sections as a function of epsilon are reported and show excellent agreement with experimental measurements of the energy distribution of emitted electrons in PI and AI of Ar by He* (1s2s,3S). (Auth.)