Pulse radiolysis studies of the de-excitation processes of excited argon atoms by N 2, H 2, and D 2

Abstract

The optical emissions of H 2( 3Σ g + → b 3Σ u +) and D 2(a 3Σ g + ]ar b 3Σ u +) have been observed by pulse radiolysis of ArH 2 and ArD 2 mixtures, respectively. These emissions are considered to be induced by energy transfer from an excited argon atom (Ar*) to hydrogen or deuterium. The precursor of H 2(a 3Σ g +) or D 2(a 3Σ g +) may be considered to be a highly excited argon atom. From the kinetic data, the energy transfer rate constants in each mixture are obtained to be k(Ar* + H 2) = (8.2 ± 0.4) × 10 −11 cm 3 molecule −1 s −1 and k(Ar* + D 2) = (6.8 ± 0.3) × 10 −11 cm 3 molecule −1 s −1. The optical emissions of the second positive emission of nitrogen (C 3Π u → B 3Π g) and the first positive emission of nitrogen (B 3Π g → A 3Σ u +) have also been observed in ArN 2 mixtures. These emissions are considered to be induced by energy transfer from the lowest metastable states of argon Ar( 3P 0,2) to nitrogen, whose rate constant is obtained to be k(Ar( 3P 0,2) + N 2) = (2.3 ± 0.1) × 10 −11 cm 3 molecule −1 s −1.