通过双色红外-真空紫外激光光电离-光电子方法测量丙炔在2934 - 2952厘米⁻¹区域的振转跃迁归属

Assignment of rovibrational transitions of propyne in the region of 2934-2952 cm(-1) measured by two-color IR-vacuum ultraviolet laser photoion-photoelectron methods.

作者信息

Xing Xi, Reed Beth, Lau Kai-Chung, Baek Sun-Jong, Bahng Mi-Kyung, Ng C Y

机构信息

Department of Chemistry, University of California, Davis, Davis, California 95616, USA.

出版信息

J Chem Phys. 2007 Jul 28;127(4):044313. doi: 10.1063/1.2748403.

DOI:10.1063/1.2748403

PMID:17672696

Abstract

The infrared (IR) spectrum of propyne in the region of 2934-2952 cm(-1) has been recorded by the IR-vacuum ultraviolet (VUV)-photoion method. The spectrum is shown to consist of two near-resonant, but noncoupled vibrational bands: the nu2 symmetric methyl C-H stretching vibrational band and a combination vibrational band nucs. The previously unobserved Q line of the nucs band is observed. The rotational transition lines of the nu2=1 band produces IR-VUV-pulsed field ionization-photoelectron (IR-VUV-PFI-PE) signal at the C3H4+ (nu2+=1) photoionization threshold. The rotational transition lines associated with the nucs band do not produce IR-VUV-PFI-PE signal. Rotational transition lines of both vibrational bands are assigned and simulated; and ab initio calculations further confirm the assignment.

摘要

采用红外-真空紫外（IR-VUV）光离子化方法记录了丙炔在2934 - 2952 cm⁻¹区域的红外（IR）光谱。该光谱显示由两个近共振但非耦合的振动带组成：ν₂对称甲基C - H伸缩振动带和一个组合振动带νcs。观察到了之前未观测到的νcs带的Q线。ν₂ = 1带的转动跃迁线在C₃H₄⁺（ν₂⁺ = 1）光离子化阈值处产生红外-真空紫外脉冲场电离光电子（IR-VUV-PFI-PE）信号。与νcs带相关的转动跃迁线不产生IR-VUV-PFI-PE信号。对两个振动带的转动跃迁线进行了归属和模拟；从头算计算进一步证实了归属。