De-excitation Rate Constants for Helium Metastable Atoms with Several Atoms and Molecules

Abstract

The de-excitation rate constants for He(21S) and He(23S) metastables have been measured with the following gases: Ne, Ar, Kr, Xe, H2, D2, N2, CO, NO, O2, CO2, NO2, NH3, SF6, CH4, C2H6, C3H8, and C4H10. These rate constants were measured in a flowing afterglow system using the neon 5689.8 and 7032.4-Å emission lines as detectors for the He(21S) and He(23S), respectively. In all of the above cases the He(21S) rate constants were several times faster than those of the He(23S).