The formation ratio of the two spin-orbit states, 3P0 / 3P2, of the metastable argon, Ar*, was investigated by the glow discharge of a pulsed Ar supersonic beam. The 3P0 / 3P2 ratio decreased with the increase of the glow discharge potential Vg, by which the electron bombardment initiates the discharge. The observed Vg-dependence clearly showed an inverse behavior against Vg as compared with that in the conventional electron impact by low beam densities.

A large steric effect on XeBr* formation was observed in the reaction of oriented CF 3 Br with Xe( 3 P). The reaction cross-section was found to be largest for the Br-end collisons and smallest for the CF 3 -end collisions, even though the electron transfer takes place at relatively large internuclear distances in the entrance channel. The large orientational dependence may be attributed to the fraction of the collisions that have small impact parameters which can lead to the formation of XeBr*. The majority of the collisions, having larger impact parameters, are supposed to lead to electron back-transfer in the exit channel and are relatively insensitive to the reactant orientation.