Department of Chemistry, Howard University, Washington, District of Columbia 20059, USA.
J Chem Phys. 2012 Jan 21;136(3):034307. doi: 10.1063/1.3676782.
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.
报道了 amidogen 自由基 NH(2)(Ã(2)A(1))的第一电子激发态的辐射寿命，使用激光诱导荧光研究了选定振动能级 ν(2)’中转动态的辐射寿命。在微波放电流动系统中，氩气 (Ar(∗)((3)P(0), (3)P(2))亚稳原子与氨 (NH(3))分子发生热碰撞，生成基态 NH(2)(X̃(2)B(1))。通过测量 NH(2)(Ã(2)A(1) → X̃(2)B(1))的衰减曲线，确定了 NH(2)(Ã(2)A(1))的去活化辐射寿命。除了与基态的 Fermi 共振会延长辐射寿命外，还观察到辐射寿命随转动量子数的系统增加。此外，(0, 9, 0) Γ，τ(1) = 18.65 ± 0.47 μs 和 (0, 8, 0) Φ，τ(2) = 23.72 ± 0.65 μs 能级的平均辐射寿命远长于 (0, 9, 0) Σ，τ(3) = 10.62 ± 0.47 μs，和 (0, 8, 0) Π，τ(4) = 13.55 ± 0.55 μs 状态，表明第一电子激发态和基态之间的混合增加。
