Article

Variation of Radiative Lifetimes of NH2(Ã2A1) with Rotational Levels in the (0,8,0) and (0,9,0) Vibration Bands

The Journal of Chemical Physics (Impact Factor: 3.12). 01/2012; 136(3).

ABSTRACT Radiative lifetimes from the first electronically excited state of the amidogen free radical, NH2(Ã2A1), are reported for rotational states in selected vibrational levels ν2� using laser-induced fluorescence. Thermal collision of argon, Ar*(3P0, 3P2) metastable atoms in a microwave discharge- flow system with ammonia (NH3) molecules produced ground state NH2(X ̃2B1). The radiative lifetimes for the deactivation of NH2(Ã2A1) were determined by measuring the decay profiles of NH2 (Ã2 A1 → X ̃ 2 B1 ). In addition to the Fermi resonances with the ground state that lengthen the ra- diative lifetimes, a systematic increase in the radiative lifetimes with rotational quantum number was observed. Furthermore, the average radiative lifetimes of the (0, 9, 0) 􏰀, τ1 = 18.65 ± 0.47 μs and (0, 8, 0) 􏰁, τ2 = 23.72 ± 0.65 μs levels were much longer than those of the (0, 9, 0) 􏰂, τ3 = 10.62 ± 0.47 μs, and (0, 8, 0) 􏰃, τ 4 = 13.55 ± 0.55 μs states suggesting increased mixing of the first elec- tronic excited and the ground states. © 2012 American Institute of Physics.[doi:10.1063/1.3676782]

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