HE-0+N-2 COLLISIONS AT 1.0 KEV

He-0+N-2 collisions are studied at an energy of 1.0 keV and in an angu lar range from 0.2 degrees to 2 degrees. Time-of-flight techniques are used to identify the dominant collision processes. Electronically ela stic collisions are found to dominate the scattering for angles out to 1.3 degrees. In He-0+N-2, H-2, and O-2 collisions the electronically elastic processes were found to be weak beyond the smallest angles, in sharp contrast to the present results, Excitation of N-2 (a 1 Pi(g)) is found to be the dominant small-angle inelastic process. Our results also show excitation of N-2(+) (A (2) Pi(u) and B (2) Sigma(u)(+)) bu t at most very weak excitation of the N-2(+) (X (2) Sigma(g)(+)) groun d state. The excitation of an electron from the 3 sigma(g) molecular o rbital of N-2 is found to be generally quite specific and takes place primarily through a transition to a 1 pi(g) orbital. [S1050-2947(98)01 402-4].