Processes of quenching of 4,3He(21S, 21P) states in He+N2 mixture

Abstract

The quenching process of He (21S, 21P) states by collisions with nitrogen molecules in a He+N2 mixture at low pressure is experimentally investigated by a time-resolved spectroscopy method combined with pulse electron excitation. The influence of nitrogen atoms in quenching process is taken into account. The rate constants and corresponding cross sections for quenching 4He(21S), 4He(21P), 3He(21S) and 3He(21P) states by collisions with ground state N2 molecules at Tg=600 K are: k[4He(21S)] = (2.7±0.1)x10-10 cm3s-1, k[4He(21P)] = (1.9±0.3)x10-9 cm3s-1, k[3He(21S)] = (2.8±0.1)x10-10 cm3s-1, and k[3He(21P)] = (3.2±0.6)x10-9 cm3s-1 and σ[4He(21S)] = (14.2±0.5)x10-16 cm2, σ[4He(21P)] = (100±16)x10-16 cm2, σ[4He(21S)] = (12.7±0.5)x10-16 cm2, and σ[4He(21P)] = (145±27)x10-16 cm2.