ELECTRON-CAPTURE IN H++N2 COLLISIONS

Electron capture in H+ + N2 collisions is studied at small scattering angles and energies in the range from 0.5 to 3.0 keV. The important co llision processes are identified using time-of-flight techniques for e nergy analysis. Our results show that the quasiresonant H+ + N2 --> H( 1s) + N2+(X) channel dominates the electron capture only at the smalle st angles. As an example, at 1.0 keV, capture to this channel occurs w ith a probability less than 0.5 for scattering angles beyond 0.7-degre es. The reduced cross section for excitation of the quasiresonant chan nel shows a maximum which moves to larger reduced scattering angles wi th increasing projectile energy. A second important process, populatin g H(1s) + N2+(C) is found. Although the excitation of this channel inv olves a multielectron rearrangement it is found to dominate over the ' 'one-electron'' H(n=2) + N2+(X) channel which lies close in energy. W e also find that the electron capture, even at small scattering angles , can generate highly excited N2+ states.