Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
Phys Chem Chem Phys. 2018 Oct 17;20(40):25806-25811. doi: 10.1039/c8cp04780d.
We report the observation of a rotationally resolved ν6 band associated with the OO-stretching mode of the simplest Criegee intermediate, CH2OO, in the range of 879.5-932.0 cm-1 (11.37-10.73 μm) at an optical resolution of 0.0015 cm-1. The spectra were recorded with a tunable cw external-cavity quantum-cascade laser (EC-QCL) system coupled with a Herriott multipass absorption cell. Over one thousand lines were assigned to determine the rovibrational parameters of the ν6 band. Rotational parameters A', B', and C' and higher-order parameters ΔJ, ΔJK, ΔK, δJ, and δK were determined precisely. Rotational perturbations for Ka' = 3, Ka' = 6, and Ka' ≥ 11 on high-J levels were observed. In particular, for Ka' = 6, frequency shifts as a function of J' showed an avoided crossing; the shifts were analyzed in terms of a Coriolis interaction between modes ν6 and ν8 of CH2OO. According to the distinct temporal profiles, lines of a hot band near 899.5 cm-1 were also identified.
我们报告了在 0.0015cm-1 的光学分辨率下，在 879.5-932.0cm-1（11.37-10.73μm）范围内观察到与最简单的克里格中间体 CH2OO 的 OO 伸缩模式相关的ν6 带的旋转分辨。光谱是用可调谐连续波外腔量子级联激光器（EC-QCL）系统与 Herriott 多通吸收池耦合记录的。分配了一千多条线来确定ν6 带的振转参数。精确确定了ν6 带的 A'、B'和 C'转动参数以及更高阶参数ΔJ、ΔJK、ΔK、δJ和δK。观察到 Ka'=3、Ka'=6 和 Ka'≥11 的高 J 级别的旋转微扰。特别是对于 Ka'=6，J'上的频率位移显示出避免交叉；根据 CH2OO 的ν6 和ν8 模式之间的科里奥利相互作用，对位移进行了分析。根据明显的时间轮廓，还确定了 899.5cm-1 附近的一个热带线。
