title: Variation of radiative lifetimes of NH2(Ã2A1) with rotational levels in the (0, 8, 0) and (0, 9, 0) vibration bands.
abstract: Radiative lifetimes from the first electronically excited state of the amidogen free radical, NH(2)(Ã(2)A(1)), are reported for rotational states in selected vibrational levels ν(2)' using laser-induced fluorescence. Thermal collision of argon, Ar(∗)((3)P(0), (3)P(2)) metastable atoms in a microwave discharge-flow system with ammonia (NH(3)) molecules produced ground state NH(2)(X̃(2)B(1)). The radiative lifetimes for the deactivation of NH(2)(Ã(2)A(1)) were determined by measuring the decay profiles of NH(2)(Ã(2)A(1) → X̃(2)B(1)). In addition to the Fermi resonances with the ground state that lengthen the radiative lifetimes, a systematic increase in the radiative lifetimes with rotational quantum number was observed. Furthermore, the average radiative lifetimes of the (0, 9, 0) Γ, τ(1) = 18.65 ± 0.47 μs and (0, 8, 0) Φ, τ(2) = 23.72 ± 0.65 μs levels were much longer than those of the (0, 9, 0) Σ, τ(3) = 10.62 ± 0.47 μs, and (0, 8, 0) Π, τ(4) = 13.55 ± 0.55 μs states suggesting increased mixing of the first electronic excited and the ground states.
authors.affiliation: Department of Chemistry, Howard University, Washington, District of Columbia 20059, USA. mndoum1@umbc.edu
authors.forename: Marc
authors.initials: M
authors.lastname: N'Doumi
authors.forename: Joshua B
authors.initials: JB
authors.lastname: Halpern