Teodoro T Q, Koenis M A J, Rüger R, Galembeck S E, Buma W J, Nicu V P, Visscher L
Departamento de Química , FFCLRP, Universidade de São Paulo , Avenida Bandeirantes 3900 , Ribeirão Preto , 14040-901 São Paulo Brazil.
Amsterdam Center for Multiscale Modeling, Faculty of Science , Vrije Universiteit Amsterdam , de Boelelaan 1083 , 1081 HV Amsterdam , The Netherlands.
J Phys Chem A. 2018 Dec 13;122(49):9435-9445. doi: 10.1021/acs.jpca.8b08218. Epub 2018 Nov 30.
Vibrational circular dichroism (VCD) is a spectroscopic technique used to resolve the absolute configuration of chiral systems. Obtaining a theoretical VCD spectrum requires computing atomic polar and axial tensors on top of the computationally demanding construction of the force constant matrix. In this study we evaluated a VCD model in which all necessary quantities are obtained with density functional based tight binding (DFTB) theory. The analyzed DFTB parametrizations fail at providing accurate vibrational frequencies and electric dipole gradients but yield reasonable normal modes at a fraction of the computational cost of density functional theory (DFT). Thus, by applying DFTB in composite methods along with DFT, we show that it is possible to obtain accurate VCD spectra at a much lower computational demand.
振动圆二色性（VCD）是一种用于解析手性体系绝对构型的光谱技术。要获得理论VCD光谱，除了构建力常数矩阵这一计算量很大的工作之外，还需要计算原子极化张量和轴向张量。在本研究中，我们评估了一种VCD模型，其中所有必要的量都是通过基于密度泛函的紧束缚（DFTB）理论获得的。所分析的DFTB参数化方法在提供准确的振动频率和电偶极梯度方面存在不足，但能以密度泛函理论（DFT）计算成本的一小部分产生合理的简正模式。因此，通过在复合方法中将DFTB与DFT一起应用，我们表明在低得多的计算需求下获得准确的VCD光谱是可能的。
