Quenching of the lowest-lying metastable excimer of argon by N2 and effects of ’’three-body’’ Ar(1s) quenching on the yield of Ar2(3Σ+u)

Fast absorption spectrophotometry has been used to monitor the growth and decay of the Ar2(3Σ+u) excimer species at 992 nm in argon–nitrogen mixtures following passage of single pulses of a high current, high energy electron beam. The rate constant for electronic energy transfer to N2 is equal to 2.24 (±0.08)10−12 cm3 molecule−1 s−1 at 294 K. The yield of Ar2(3Σ+u) is found to be markedly enhanced relative to predictions based on the total quenching efficiencies of N2 for the Ar(1s) atoms. This enhancement is attributed to ’’three-body’’ quenching by N2, i.e., vibrational and rotational relaxation of dissociative excimer molecules formed by two-body Ar(1s)+Ar(1S0) combinations.