Selective production and kinetic analysis of thermally equilibrated N2(B 3Πg, v = 0) and N2(W 3Δu, v = 0)

Abstract

The kinetic behavior of triplet-state molecular nitrogen, N₂(B ³Π_g, v = 0) and N₂(W ³Δ_u, v = 0), was examined. These molecules were produced by excitation transfer between Xe(6s[3/2]₁) and ground-state N₂ followed by collisional vibrational relaxation. Xe(6s[3/2]₁) was produced by two-photon laser excitation of Xe(6p[1/2]₀) followed by concomitant amplified spontaneous emission (ASE). The weighted averages of the rate constants for the quenching of N₂(B, v = 0) and N₂(W, v = 0) were determined for 15 molecules by measuring the decay profiles of N₂(B, v = 0). The observed rate constants are all one order of magnitude smaller than those reported for N₂(B, v ≥ 1). The literature values for N₂(B, v ≥ 1) must be the rate constants to produce neighbouring N₂(W), from which N₂(B) can be reproduced, and do not represent those for net quenching. In the reaction with H₂(D₂), the production of H(D) atoms was confirmed to be one of the major exit channels, while the relaxation to N₂(A ³Σ⁺_u) was found to be minor.