Vibrational Circular Dichroism and Electronic Currents from First Principles

振动圆二色性（VCD）是一种新兴的光谱技术，在学术界和工业界的应用范围越来越广。参考左右圆偏振光的吸收差异，VCD可以被认为是“手性IR光谱”。它已成为一个宝贵的工具，在确定的绝对配置分配记录光谱的结构信息从理论计算。然而，VCD对手性中心周围的超分子效应高度敏感，无论是溶液光谱对溶剂的依赖性还是固态手性晶体堆积的影响。一个关键点在于有效的理论模型的可用性，在解释实验结果时可以参考。由于缺乏合适的理论模型，VCD的许多应用没有实现。近年来，理论方法的财富稳步增长-由可负担的计算能力的不断增强推动。创新的方法允许逼真的模拟，可以被视为“虚拟实验”。该项目旨在通过结合从头算分子动力学（AIMD）和核速度微扰理论（NVPT）的形式主义，推动计算化学的里程碑式创新。NVPT的理论框架最近才被实施到CPMD代码中，并等待大量的应用。AIMD+NVPT是基于非谐自由能的准确采样计算VCD光谱的一种有吸引力的方法;之前的工作已经强调了这种方法的影响。这一成功将由该项目跟进。然而，在光谱学中还有更多的应用，还有有机化学和量子化学中更基础的应用，这些应用构成了拟议研究的重要第二支柱。后者还旨在使研究人员的形象多样化，受益于东道主研究人员在量子物理和化学计算领域世界领先机构的网络和专业知识。为了以高度说明性的方式向广大受众传达理论结果，该项目明确地致力于设计可视化的指导性和教育性手段，并通过全面的Python包提高技术的易用性。

Vibrational circular dichroism (VCD) is an uprising spectroscopic technique with an increasing scope of applicability in both, academia and industry. Referring to the absorption difference of left- and right-circularly polarised light, VCD can be considered as “chiral IR spectroscopy”. It has become an invaluable tool in the determination of absolute configurations by assigning recorded spectra to structural information obtained from theoretical calculations. Yet, VCD is highly sensitive towards supramolecular effects around the chiral centre, be it the dependence of a solution spectrum on the solvent or the influence of chiral crystal packing in solid-state. A crucial point lies in the availability of efficient theoretical models that are to be referred to when interpreting experimental results. Many applications of VCD do not materialize due to the lack of suitable theoretical models. The recent years saw the wealth of theoretical methods growing steadily – fueled by continuous augmentation of affordable computational power. Innovative approaches allow for realistic simulations that can be considered as "virtual experiments". This project aims to push forward landmark innovations of computational chemistry by combining ab initio molecular dynamics (AIMD) and the formalism of Nuclear Velocity Perturbation Theory (NVPT). The theoretical framework of NVPT has only recently been implemented into the CPMD code and awaits numerous applications. AIMD+NVPT are an attractive means to compute VCD spectra based on an accurate sampling of anharmonic free energies; the preceding work has already underlined the impact if this method. This success will be followed up by this project. Yet, there are many more applications in spectroscopy, but also organic chemistry and more fundamental in quantum chemistry that form the important second pillar of the proposed research. The latter also aims for diversifying the profile of the researcher, benefiting from the host researcher's network and expertise in a world-leading institution in quantum physics and chemical computation. To communicate the theoretical results in a highly illustrative fashion to a broad audience, this project explicitly puts effort into devising instructive and educational means of visualization and to improve the techniques' ease of use through a comprehensive python package.