Spectroscopic and kinetic analysis of the VUV emissions of argon and argon-xenon mixtures. I. Study of pure argon

Abstract

The VUV luminescence spectra of argon excited by alpha particles at a few hundred Torr present two continua, at 180 and 127 nm. The 127 nm emission is very intense, it corresponds to transitions from the lowest vibrational levels of the A 1y(3 Sigma u+) and B Ou+(1 Sigma u+) states of Ar2 towards the dissociative X Og+(1 Sigma g+) ground state. The shape of the pulse corresponding to the emission of the second continuum was reconstituted by time amplitude conversion. Three exponential terms can be seen. The variation of the time constants with pressure allows a kinetic scheme for the formation and decay of the radiative molecule species to be established. The excited states of the argon molecule are created by three-body collisions, from the (1)()J=1 and (1)()J=2 states of the 3p54s configuration, the collision constants being 1.6 and 13.8 Torr-2 s-1 respectively. The radiative lifetime of the A 1u(3 Sigma u+) state is 2.86 mu s.