Formation and decay of argon and xenon molecules radiating in the vacuum ultraviolet

[摘要] 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.

[发布机构] Rice University