Huang Yu-Hsuan, Nishimura Yoshifumi, Witek Henryk A, Lee Yuan-Pern
Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan.
J Chem Phys. 2016 Jul 28;145(4):044305. doi: 10.1063/1.4958932.
We report a transient infrared (IR) absorption spectrum of the simplest deuterated Criegee intermediate CD2OO recorded using a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. CD2OO was produced from photolysis of flowing mixtures of CD2I2, N2, and O2 (13 or 87 Torr) with laser light at 308 nm. The recorded spectrum shows close structural similarity with the spectrum of CH2OO reported previously [Y.-T. Su et al., Science 340, 174 (2013)]. The four bands observed at 852, 1017, 1054, and 1318 cm(-1) are assigned to the OO stretching mode, two distinct in-plane OCD bending modes, and the CO stretching mode of CD2OO, respectively, according to vibrational wavenumbers, IR intensities, rotational contours, and deuterium-isotopic shifts predicted with extensive quantum-chemical calculations. The CO-stretching mode of CD2OO at 1318 cm(-1) is blue shifted from the corresponding band of CH2OO at 1286 cm(-1); this can be explained by a mechanism based on mode mixing and isotope substitution. A band near 936 cm(-1), observed only at higher pressure (87 Torr), is tentatively assigned to the CD2 wagging mode of CD2IOO.
我们报道了使用步进扫描傅里叶变换光谱仪与多程吸收池相结合记录的最简单的氘代克里吉中间体CD2OO的瞬态红外（IR）吸收光谱。CD2OO是通过用308 nm激光光解CD2I2、N2和O2（13或87托）的流动混合物产生的。记录的光谱显示出与先前报道的CH2OO光谱[Y.-T. Su等人，《科学》340, 174 (2013)]有密切的结构相似性。根据广泛的量子化学计算预测的振动波数、红外强度、转动轮廓和氘同位素位移，在852、1017、1054和1318 cm(-1)处观察到的四个谱带分别被指定为CD2OO的OO伸缩模式、两种不同的面内OCD弯曲模式和CO伸缩模式。CD2OO在1318 cm(-1)处的CO伸缩模式相对于CH2OO在1286 cm(-1)处的相应谱带发生了蓝移；这可以通过基于模式混合和同位素取代的机制来解释。仅在较高压力（87托）下观察到的936 cm(-1)附近的一个谱带被初步指定为CD2IOO的CD2摇摆模式。
