非键体系中计算红外光谱学的发展与应用:量子与经典体系  

Developments and applications of computational infrared spectroscopy in non-bonded systems: Quantal and classical systems

作　　者：翟羽 李佳芮 李辉 Yu Zhai;Jia-Rui Li;Hui Li(Theoretical and Computational Chemistry Laboratory,Institute of Theoretical Chemistry,Jilin University,Changchun 130012,China)

机构地区：[1]吉林大学理论化学研究所,理论化学计算实验室,长春130012

出　　处：《科学通报》2018年第33期3396-3402,共7页Chinese Science Bulletin

基　　金：国家重点研发计划(2016YFB0700801,2017YFB0203401);国家自然科学基金(21773081,21533003,91541124)资助

摘　　要：红外光谱是解析分子体系运动性质的重要方式.随着科学计算技术的不断发展以及实验探测领域的扩大,理论计算成为理解红外光谱不可或缺的手段,计算红外光谱学应运而生.在以非键相互作用为连接纽带的体系中,由于分子的运动情况复杂,所对应的红外光谱难以用经验指认,理论计算显得格外重要,并逐渐成为了目前理论计算化学的研究热点之一.本文回顾了可以用于非键体系光谱精度计算的一系列方法,从第一性原理出发,通过合理的近似,能够较好地复现实验结果,并且可以获得从光谱学不能直接得到的信息.回顾从小体系到大体系红外光谱的发展思路,本文亦对该领域的未来发展方向做了展望.Infrared（IR） spectroscopy, responding to molecular vibrations, is one of the most important tools in understanding the behavior of molecules. For complex systems, because of the relatively dense spectra lines, it could be very difficult to assign IR spectra merely by experience, an instance of which is non-bonded system. For middle-size system, theory and computation, however, can handle part of this problem by construct the potential energy surfaces（PESs） of system following a nuclear motion calculation classic or quantum mechanically. For large-size non-bonded system, although it is hard to calculate the properties of the whole system directly, by decomposing the system into quasi-isolated parts, the spectra can be calculated from the first principle using some approximations, which belong to the toolchain of computational spectroscopy. In this review, we recall some of these methodology based on perturbation theory.（1） In the research of van der Waals complexes, intramolecular vibrations are separated from intermolecular motion via Born-Oppenheimer approximation and first order Rayleigh-Schrodinger perturbation theory. For the ground and first excited state of the chromophores, rigid body intermolecular PESs are build including the relative orientation of the rigid molecules. Based on the intermolecular PESs, rotation and intermolecular radial stretching are treated using Discrete Variable Representation/Finite Basis Representation（DVR/FBR） fully quantum mechanically. The rovibrational spectra are then obtained by the gap between energy levels and the transition dipole moments.（2） Spectroscopy of quantum clusters, where chromophores molecules are caged in helium or hydrogen molecules solvent, are another important topic where perturbation theory and quantum simulation get involved. As previous systems, accurate two-body intermolecular PESs are also needed. The potential of the system is then represented by the many-body expansion, often truncated at two-body term. Quantum effect of the rigi

关 键 词：非键体系 理论红外光谱学 量子振动微扰 

分 类 号：O657.33[理学—分析化学]