通过超快时间频率分辨相干反斯托克斯拉曼散射追踪多原子小分子液体中的分子内振动再分布

Tracking Intramolecular Vibrational Redistribution in Polyatomic Small-Molecule Liquids by Ultrafast Time-Frequency-Resolved CARS.

作者信息

Liu Xiaosong, Zhang Wei, Song Yunfei, Yu Guoyang, Zheng Zhaoyang, Zeng Yangyang, Lv Zhe, Song Huajie, Yang Yanqiang

机构信息

Department of Physics, Harbin Institute of Technology , Harbin 150001, China.

National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics , Mianyang 622150, China.

出版信息

J Phys Chem A. 2017 Jul 6;121(26):4948-4952. doi: 10.1021/acs.jpca.7b05578. Epub 2017 Jun 22.

DOI:10.1021/acs.jpca.7b05578

PMID:28610422

Abstract

Selective excitation of C-H stretching vibrational modes, detection of intramolecular vibrational energy redistribution (IVR), and vibrational modes coupling in the electronic ground state of benzene are performed by using femtosecond time- and frequency-resolved coherent anti-Stokes Raman scattering (CARS) spectroscopy. Both of the parent modes in the Raman-active bands are coherently excited by an ultrafast stimulated Raman pump, giving initial excitations of 3056 cm (A) and 3074 cm (E) and subsequent IVR from the parent modes to daughter modes of 1181 and 992 cm, and the coherent vibrational coupling of the relevant modes is tracked. The directionality and selectivity of IVR and coherent coupling among all of the relevant vibrational modes are discussed in the view of molecular symmetry.

摘要

通过使用飞秒时间分辨和频率分辨相干反斯托克斯拉曼散射（CARS）光谱，对苯分子基态中的C-H伸缩振动模式进行选择性激发、检测分子内振动能量再分布（IVR）以及振动模式耦合。拉曼活性带中的两个母模式被超快受激拉曼泵浦相干激发，初始激发态为3056 cm⁻¹（A）和3074 cm⁻¹（E），随后从母模式到1181 cm⁻¹和992 cm⁻¹子模式的IVR过程被监测，同时追踪相关模式的相干振动耦合。从分子对称性的角度讨论了所有相关振动模式之间IVR和相干耦合的方向性和选择性。