Laser Spectroscopic Studies of a Helium Flowing Afterglow

Abstract

The reaction zone of a helium flowing afterglow has been characterized as consisting of nearly thermalized 23 S metastables in a bath of ground-state helium atoms. LIF studies show that collision-induced angular momentum scrambling occurs efficiently among the n = 3 states of helium, even to the extent of including a small amount of intersystem crossing. LOG transients have been characterized for the afterglow reaction zone, and it is proposed that these signals are associated with a pressure pulse generated by laser pumping the helium 23 S metatables.