Formation and decay of argon and xenon molecules radiating in the vacuum ultraviolet
Gleason, Robert E.
Walters, G. King
Master of Arts
The time dependence of the vacuum ultraviolet emission from dense (1-3 atm) argon and xenon is measured following excitation by a low intensity electron beam. Independent radiation is observed from the lowest excited 1Q and + states of A^ and Xej. The radiative lifetimes of these states have been determined to be 4,2 + .2 nsec (*) and 5. + .5 ^sec (lu) for argon and 5. + 1 nsec (U) and 96 + 5 nsec (lu) for xenon. The time dependence of the AZ>2 U emission indicates that the state is formed in three body collisions with a rate coefficient of 2.8 + .3 x 1 cm /sec. Because of interference from the emission from the 1Q state, a precise determination of the rate of formation of the Xe2 U state is not possible. By considering the pressure dependence of both the decay time and the intensity of the emission from Xe2 *, the production rate of the state has been estimated to be approximately 2 x 1 cra^/sec. Under the excitation conditions of this experiment, the emission from the U state was found to be about 1 - 15Z of that from lu for both gases at pressures of a few atmospheres. The ratio of + to lu emission decreases at lower pressures.