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Elementary reactions of NH (a 1 Δ) and NH(X 3 Σ) with N, O and NO

1994; Volume: 98; Issue: 2 Linguagem: Inglês

10.1002/bbpc.19940980204

0005-9021

W. Hack, H. Gg. Wagner, A. Yu. Zasypkin,

Plasma Applications and Diagnostics

Abstract The elementary reactions of NH(a 1 Δ) with N, O, and NO and the reactions of NH(X 3 Σ − ) with N, O and NO were studied in a quasi static laser flash photolysis cell at room temperature ( T =298T) and low pressures (15≤ p /mbar≤20). NH(a) was produced by HN 3 laser photolysis at λ = 248 nm. NH(X) was obtained from the fast quenching of NH(a) with Xe. The O atom source was the NO + N reaction ([N] 0 >>[NO] 0 ), with N atoms formed in a microwave discharge of N 2 /He. NH(a), NO(X) and the primary products NH(X), OH(X) and NO (X) were detected by pulsed laser induced fluorescence (LIF). The absolute N atom concentrations were determined via the reaction of N with NO. Time resolution was achieved by time delay between photolysis and probe laser pulses. For overall depletion: magnified image the following rate constants were obtained: k 1 , = (6.0±1.5)·10 11 cm 3 /(mol·s); k 2 = (5.6±2)·10 12 cm 3 /(mol·s); and k 3 = (1.8±0.2)·10 13 cm 3 (mol·s). By fitting the NH(X) concentration profiles, determined experimentally, with computer simulations, the following rate constants for quenching channels were obtained: k 1q = (6.0±1.2)·10 11 cm 3 /(mol·s) and k 2q = (1.2±0.3)·10 12 cm 3 /(mol·s). For the reaction pathways of reaction (2): magnified image