Modeling of London Dispersion Interactions in Molecular Chemistry

通过现代量子化学方法对伦敦色散相互作用及其“化学”分析的准确描述是该项目的中心主题。基于我们对色散校正平均场（DFT-D/NL）方法的见解和经验，我们将继续致力于在三个领域的项目中获得对分子系统中伦敦色散相互作用的彻底理解和量化：方法开发，与其他参与者在理论上困难或非标准情况下的联合应用和支持。详细地说，下面的主题将被考虑：-自动生成的构象集成和簇结构，即使对于大的系统，由一个新的，分别开发了基于强大而精确的紧密结合量子化学方法和新的分子间力场的复合程序，-溶液中的分子热化学和反应障碍和机制的计算，重点是色散控制，-非共价相互作用的能量分解分析，以揭示色散的重要性，特别是关于色散能量供体（DED）与反DED（去稳定）行为，-进一步发展包括多体色散效应的D4模型-非局部VV10密度泛函与激发态量子化学方法的耦合以及涉及电子激发的实验的解释。特别注意色散对感兴趣的化学性质的影响。通过应用色散校正密度泛函方法，这在技术上和概念上都很容易实现，因为假设电子和色散能量是可加的，校正可以很容易地打开/关闭。此外，所提出的D4模型（与D3相比）将允许研究色散效应的电荷依赖性，特别是对于金属系统，以及更准确地考虑多体色散能量。新的DFT-D4方法的更高精度与改进的采样技术相结合，将导致总体上显著提高处理的可靠性。

The accurate account of London dispersion interactions and their 'chemical' analysis by modern quantum chemical methods are the central themes of this project. Based on our insight and experience with dispersion corrected mean-field (DFT-D/NL) methods we will continue to contribute to gaining a thorough understanding and quantification of London dispersion interactions in molecular systems with projects in the three areas: method development, joint applications with and support of other participants in theoretically difficult or non standard cases. In detail, the following topics will be considered:- automatic generation of conformation ensembles and cluster structures even for large systems by a new, separately developed composite procedure based on a robust and accurate tight-binding quantum chemical method and the new intermolecular force field,- molecular thermochemistry in solution and computation of reaction barriers and mechanisms with an emphasis on dispersion control,- energy decomposition analysis of non-covalent interactions to reveal the importance of dispersion in particular regarding dispersion energy donor (DED) vs. anti-DED (de-stabilising) behavior,- further development of the D4 model including many-body dispersion effects- coupling of the non-local VV10 density functional with excited state quantum chemistry methods and interpretation of experiments involving electronic excitationParticular attention will be paid to the effect of dispersion on the chemical property of interest. With the applied dispersion corrected density functional methods this is technically and conceptually easily possible because the electronic and dispersion energies are assumed to be additive and the correction can easily be switched on/off. In addition the proposed D4 model (in comparison to D3) will allow to investigate the charge dependence of dispersion effects in particular for metallic systems as well as a more accurate consideration of the many-body dispersion energy. The higher accuracy of the new DFT-D4 methods in combination with improved sampling techniques will lead to overall significantly increased reliability of the treatments.