吸收发射光谱非平衡溶剂效应的连续介质模型

In modern computational chemistry, theoretical simulation of the electronic absorption/emission spectra in condensed phase presents itself as a hot andprofound topic due to the fact that many physical processes and biochemistry.reactions occur in solution. A feasible way to take such solvent effect on the electronic spectra into account is to establish a suitable and reasonable solvation model. Considering the deficiencies and misunderstandings in the traditional solvation models, this project will first propose, on the basis of the thermodynamics of constrained equilibrium principle, the correct expression of the nonequilibrium solvation energy for the ultrafast electron transition processes in solution.Then, a numerical model for the solvent effect estimation will be developed under the situation of arbitrary solute cavity by employing the technique of grid partition of the cavity surface. Thirdly, another brilliant point of this project is the development of theoretical methods to evaluate the solvation energy for excited states, combining the state-of-the-art TDDFT technology of the geometry optimization for excited states by analytical energy gradients. The ultimate goal of this proposal is to develop a new theoretical model and the applicable numerical program in order for the solvation energy calculation of the excited states in solution and the spectral shifts for photon absorption/emission in the presence of solvents, within the framework of continuous medium theory

溶剂环境下电子吸收/发射光谱的理论计算是目前计算化学研究的重要方面，而正确考虑溶剂效应的理论模型则是实现光谱溶剂效应计算的基础。本课题针对光谱溶剂化理论模型中存在的问题，基于外场约束平衡的基本热力学原理，经过严格推演，在理论上建立电子跃迁过程非平衡溶剂化能和吸收/发射光谱的溶剂化移动的合理表达式；在数值计算方面，将结合溶质孔穴表面剖分技术，发展任意孔穴条件下溶剂效应的计算方法;结合TDDFT激发能解析能量梯度方法，发展激发态溶剂化能计算的理论模型，形成基于连续介质模型的激发态和吸收发射光谱计算的新方法和新程序,应用于电子吸收/发射光谱的理论计算.

电子光谱理论模型中的溶剂化效应是目前溶剂环境下电子光谱理论计算的难点。本课题基于基本热力学原理，建立溶剂化移动的合理表达式，发展吸收/发射光谱的量子力学/连续介质模型的数值解方法，结合TDDFT方法实现电子跃迁非平衡溶剂化能的计算，解决现有电子吸收和发射光谱中溶剂化效应的计算问题。本项目取得以下主要成果：（1）通过外场约束平衡的热力学原理，建立了电子跃迁过程非平衡溶剂化能和吸收/发射光谱的溶剂化移动的合理表达式；（2）结合溶质孔穴表面分割技术，发展了任意孔穴条件下溶剂效应的计算方法，建立了非球孔穴条件下电子吸收/发射光谱溶剂化移动的离散形式，发展了求解离散极化电荷和非平衡溶剂化能的计算程序；（3）结合TDDFT激发能解析能量梯度方法，在不考虑溶质和溶剂相互极化效应的情形下，计算了离散化形式的非平衡溶剂化能，发展了计算光谱溶剂化移动的计算程序；（4）基于TDDFT/PCM以及态特定方法，在Q-Chem中分别实现了在基态反应场和激发态反应场中电子吸收/发射光谱溶剂化移动的计算程序。（5）运用课题组已开发的非平衡溶剂化效应的连续介质模型得到典型溶质分子在溶剂中的非平衡溶剂化能和溶剂重组能，实现了溶剂环境下电子激发过程和垂直电离过程溶剂化效应的理论计算。项目发表第一标注SCI论文6篇，培养博士生2人（已毕业），硕士生3人(已毕业1人)，已经超额达到了项目预期的目标。