Decay of the first triplet Ne2 excimer in the presence of O2

Abstract

Measurements of the rate of decay of the first triplet state of the Ne2 molecule in Ne/O2 mixtures have been performed by fast spectrophotometric monitoring of this species at 814 nm. The rate constant for electronic quenching of vibrationally relaxed Ne2 (3Σu+) by O2 has been found to be equal to 3.67 (±0.14)10−10 cm3 molecule−1 s−1 at 298 K. A new upper limit to the value of the spontaneous radiative decay constant is equal to 1.28(±0.02) 105 s−1. Dependence of the excimer yield on O2 concentraion appears to indicate that electronic three-body quenching of the atomic precursor(s) predominates markedly over vibrational relaxation of Ne2(3Σu+, v). The excimer yield is, accordingly, extremely sensitive to the presence of impurities at high neon pressures.