Coupling of Electron Momenta in Ion-Atom Collisions

Abstract

Coupling of electron momenta is considered for the resonant charge exchange process in slow collisions. Since electron transfer proceeds at large distances between colliding particles compared to their sizes, where ion-atom interactions are relatively weak, one can separate different types of interactions and ascertain the character of coupling of electron momenta in a quasimolcculc consisting of colliding ion and atom under real conditions. The number of types of interactions for colliding particles exceeds that used in the classical Hund scheme of momentum coupling. Momentum coupling in the case of halogen and oxygen atoms is outside the Hund scheme. In these cases of resonant charge exchange, the quantum numbers of the quasimolcculc in the course of electron transfer are the total momenta J, j of colliding atom and ion, and the projection M or M j of the atom orbital or total momentum onto the molecular axis. The ion-atom exchange interaction potential does not depend on the ion fine state, and the resonant charge exchange process is not entangled with processes of rotation of electron momenta under these conditions, as it takes place in the case “a” of Hund coupling. The partial cross section of the resonant charge exchange process depends on quantum numbers of colliding particles, while the average cross section depends weakly on the coupling scheme.