Investigation and modelling of dispersion interactions in electronically excited states and the effects of dispersion interactions on electronic excitations

电子激发态色散相互作用的研究和建模以及色散相互作用对电子激发的影响

• 批准号: 398047156
• 负责人: Professor Dr. Christof Hättig
• 金额: --
• 依托单位: Lehrstuhl für Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398047156?language=en
• 关键词: Investigation; modelling; dispersion; interactions; electronically

The aim of the project is to achieve a better understanding of the connection between the electronic excitations in a chromophore and its dispersion interaction with an environment. Important research questions that will be addressed are: In which chemical situations and for which kind of electronically excited states is it important to account for the change of the dispersion interaction upon electronic excitation in its quantum chemical description? Are there situations and/or chromophores where the dispersion interaction with the environment changes significantly the excitation energy or the electronic structure of the excited state or the order of the excited states?An additional object of the project is the development of the dispersion contribution to the self-consistent reaction field model PE (polarizable embedding) which accounts for the dispersion interaction during the calculation of the wavefunction parameters for the ground and electronically excited states. A posteriori corrections will thereby be avoided because they lead in general to qualitatively wrong potential energy surfaces in the vicinity of avoided crossings. This is done because we aim at a QM/MM method, which includes the dispersion interaction upon electronic excitation processes and is suitable for the calculation of excited state structures and relaxation processes. This will be implemented at the example of the PERI-ADC(2) and PERI-CC2 methods.For the computation of dispersion coefficients for larger molecules with a correlated wavefunction method we will in addition extend an existing RI-CC2 code for frequency-dependent polarizabilities in ground and excited states for imaginary frequency and for the calculation of Cauchy moments.

该项目的目的是更好地理解发色团中的电子激发及其与环境的色散相互作用之间的联系。将解决的重要研究问题是：在哪种化学情况下以及哪种电子激发态中，在量子化学描述中解释电子激发时色散相互作用的变化很重要？是否存在色散与环境相互作用显着改变激发能或激发态电子结构或激发态顺序的情况和/或发色团？该项目的另一个目标是开发色散对自洽反应场模型 PE（极化嵌入）在计算基态和电子激发态的波函数参数时考虑了色散相互作用。因此将避免后验校正，因为它们通常导致在避免的交叉点附近产生定性错误的势能表面。这样做是因为我们的目标是 QM/MM 方法，该方法包括电子激发过程中的色散相互作用，适合计算激发态结构和弛豫过程。这将在 PERI-ADC(2) 和 PERI-CC2 方法的示例中实现。为了使用相关波函数方法计算较大分子的色散系数，我们将另外扩展现有的 RI-CC2 代码，用于频率相关的用于虚频率和柯西矩计算的基态和激发态极化率。