Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
J Chem Theory Comput. 2022 Oct 11;18(10):6217-6230. doi: 10.1021/acs.jctc.2c00736. Epub 2022 Sep 16.
The paper illustrates the Activity Weighted Velocities (AWV) methodology to compute Vibrational Circular Dichroism (VCD) anharmonic spectra from Density Functional Theory (DFT) molecular dynamics. AWV calculates the spectra by the Fourier Transform of the time correlation functions of velocities, weighted by specific observables: the Atomic Polar Tensors (APTs) and the Atomic Axial Tensors (AATs). Indeed, AWV shows to correctly reproduce the experimental spectra for systems in the gas and liquid phases, both in the case of weakly and strongly interacting systems. The comparison with the experimental spectra is striking especially in the fingerprint region, as demonstrated by the three benchmark systems discussed: (1)-Fenchone in the gas phase, ()-(-)-Propylene oxide in the liquid phase, and ()-(-)-2-butanol in the liquid phase. The time evolution of APTs and AATs can be adequately described by a linear combination of the tensors of a small set of appropriate reference structures, strongly reducing the computational cost without compromising accuracy. Additionally, AWV allows the partition of the spectral signal in its molecular components without any expensive postprocessing and any localization of the charge density or the wave function.
本文介绍了一种基于密度泛函理论（DFT）分子动力学计算振动圆二色性（VCD）非谐谱的活性加权速度（AWV）方法。AWV 通过对速度的时间相关函数进行傅里叶变换，并对特定的观测值（原子极性张量（APT）和原子轴向张量（AAT））进行加权来计算光谱。实际上，AWV 能够正确重现气相和液相中弱相互作用和强相互作用体系的实验光谱。与实验光谱的对比非常显著，尤其是在指纹区域，文中通过三个基准体系（1）气相中的法呢酮、（2）液相中的（-）-（-）-环氧丙烷和（3）液相中的（-）-（-）-2-丁醇进行了演示。APT 和 AAT 的时间演化可以通过一小部分合适参考结构的张量的线性组合来充分描述，这大大降低了计算成本，而不会影响准确性。此外，AWV 允许在不进行任何昂贵的后处理和任何电荷密度或波函数定位的情况下，将光谱信号分解为其分子成分。
