Electron capture in H++N2 collisions.

Abstract

Electron capture in H[sup +]+N[sub 2] collisions is studied at small scattering angles and energies in the range from 0.5 to 3.0 keV. The important collision processes are identified using time-of-flight techniques for energy analysis. Our results show that the quasiresonant H[sup +]+N[sub 2][r arrow]H(1[ital s])+N[sub 2][sup +]([ital X]) channel dominates the electron capture only at the smallest angles. As an example, at 1.0 keV, capture to this channel occurs with a probability less than 0.5 for scattering angles beyond 0.7[degree]. The reduced cross section for excitation of the quasiresonant channel shows a maximum which moves to larger reduced scattering angles with increasing projectile energy. A second important process, populating H(1[ital s])+N[sub 2][sup +]([ital C]) is found. Although the excitation of this channel involves a multielectron rearrangement it is found to dominate over the one-electron'' H[sup *]([ital n]=2)+N[sub 2][sup +]([ital X]) channel which lies close in energy. We also find that the electron capture, even at small scattering angles, can generate highly excited N[sub 2][sup +] states.