（1）定义：振动圆二色谱是在红外波长区域测定分子圆二色性的一种方法。极大地扩展了圆二色谱法通过构象搜索、量子化学计算等手段准确预测手性分子的振动圆二色谱图，进而与实测谱图进行比较确定其绝对构型。是有效测定手性分子绝对构型的常规方法。
（A）Experimental VCD spectra of solvent subtracted (S)- and (R)-1 and associated noise level. (B) VCD spectrum of (S)-1, obtained as one-half the difference between enantiomer spectra, and the predicted spectra of (S, Rmp)- and (S, Smp)-1 at the B3LYP/6-31G* level.
（2）说明：The predicted VCD spectrum for (S, Rmp) shows a positive band at 1541 cm-1 and negative band at 1526 cm-1, both of roughly equal magnitudes. Visualization of the vibrations responsible for this bisignate feature reveals a combination of Amide II and C-C stretching of neighboring benzene ring. All three such amide-benzene groups are participating to produce the respective vibrations along the macrocycle. The predicted VCD spectrum for (S, Smp) shows a triplet of neighboring bands, with large positive at 1513 cm-1 and two weak negative bands one on each side. Visualization of the vibrations responsible for 1513 cm-1 band reveals it to also be a concerted Amide II and benzene ring C-C stretching vibration but localized to the benzene ring closest to the stereocenter. It is somewhat difficult to draw a definitive conclusion on the AC of 1 based solely on this region of the experimental VCD spectrum. In addition, the commonly used similarity analyses between experimental and theoretical VCD spectra are unreliable when there are only a small number of spectral features for comparison (see ESI). However, there are two experimental VCD bands that have favorable comparisons with those in the predicted spectrum for (S, Rmp), but not in that for (S, Smp).
文献来源：DOI: 10.1002/chir.23365
量子化学（quantum chemistry）是理论化学的一个分支学科，是应用量子力学的基本原理和方法研究化学问题的一门基础科学。研究范围包括稳定和不稳定分子的结构、性能及其结构与性能之间的关系；分子与分子之间的相互作用；分子与分子之间的相互碰撞和相互反应等问题。
适合的研究方向包括但不限于：有机合成、方法学研究、高分子等
可以计算的体系包括但不限于：小分子、团簇、低聚物、自由基、离子等
常用软件：Gaussian，ORCA，dmol3等
可以计算的内容包括但不限于：
分子性质，如键长键角二面角、HOMO/LUMO、电荷分布、键级、偶极矩、极化率、芳香性、静电势、Fukui函数、激发态研究等
光谱预测，如红外、紫外、拉曼、荧光、磷光、核磁、圆二色谱、旋光度等
能量计算，如结合能、解离能、电离能、弱相互作用分析等
反应相关，如过渡态搜索、势能面扫描、反应位点预测、反应路径、反应机理研究等
