Sunahori Fumie X, Smith Tony C, Clouthier Dennis J
Department of Chemistry and Biochemistry, Rose-Hulman Institute of Technology, 5500 Wabash Ave., Terre Haute, Indiana 47803, USA.
Ideal Vacuum Products, LLC, 5910 Midway Park Blvd. NE, Albuquerque, New Mexico 87109, USA.
J Chem Phys. 2020 Jan 31;152(4):044307. doi: 10.1063/1.5139527.
The ÃA-X̃B electronic transition of the jet-cooled stibino (SbH and SbD) free radical has been observed for the first time using laser induced fluorescence (LIF) detection. The radicals were produced by a pulsed electric discharge through a mixture of stibine (SbH or SbD) in high pressure argon at the exit of a pulsed molecular beam valve. SbH exhibits only three LIF bands, assigned as 2 , 0 , and 2 , with a fluorescence lifetime (τ), which decreases from ∼50 ns for 0 to <10 ns for 2. LIF transitions to the 0 (τ ∼ 2 µs), 2 (τ ∼ 400 ns), and 2 (τ ∼ 75 ns) upper vibronic states of SbD were also observed. High-resolution spectra exhibited large spin-rotation splittings and small resolved antimony hyperfine splittings due to a substantial Fermi contact interaction in the excited state. The experimentally determined rotational constants gave effective molecular structures of r = 1.724(2) Å, θ = 90.38(7)° and r = 1.693(6) Å, θ = 120.6(3)°. The ground state bending vibrational levels up to eight quanta (6404 cm) in SbH and 12 quanta (6853 cm) in SbD were measured from dispersed fluorescence spectra. All indications are that SbH undergoes a dissociative process at low vibrational energies in the excited electronic state.
利用激光诱导荧光（LIF）检测首次观测到了喷射冷却的锑化氢自由基（SbH和SbD）的ÃA-X̃B电子跃迁。这些自由基是通过在脉冲分子束阀出口处，对锑化氢（SbH或SbD）与高压氩气的混合气体进行脉冲放电产生的。SbH仅表现出三个LIF谱带，分别指定为2、0和2，其荧光寿命（τ）从0时的约50 ns降至2时的<10 ns。还观测到了向SbD的0（τ约为2 μs）、2（τ约为400 ns）和2（τ约为75 ns）上电子振动态的LIF跃迁。由于激发态中存在显著的费米接触相互作用，高分辨率光谱显示出大的自旋-旋转分裂和小的可分辨锑超精细分裂。实验测定的转动常数给出了有效分子结构，r = 1.724(2) Å，θ = 90.38(7)°以及r = 1.693(6) Å，θ = 120.6(3)°。从色散荧光光谱测量了SbH中高达八个量子（6404 cm）以及SbD中高达十二个量子（6853 cm）的基态弯曲振动能级。所有迹象表明，SbH在激发电子态的低振动能量下经历解离过程。
