An Ab Initio QM/MM-Based Approach to Efficiently Evaluate Vertical Excitation Energies in Condensed Phases Including the Nonequilibrium Solvation Effect

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• 作者：Hiroshi Nakano ; Hirofumi Sato
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：March 3, 2016
• 年：2016
• 卷：120
• 期：8
• 页码：1670-1678
• 全文大小：436K
• ISSN：1520-5207

文摘

An efficient quantum mechanical/molecular mechanics-based approach is presented to calculate a vertical excitation energy of a chromophore in condensed phases including the nonequilibrium solvation effect. The electronic polarization of a medium and the related nonequilibrium solvation effect associated with the vertical excitation are described using a polarizable solvent model. By virtue of the mean-field approximation, the target energy can be completely separated into classical and quantum mechanical parts, which enables us to efficiently evaluate the vertical excitation energy with a high-level quantum mechanical method. The method is applied to N,N-dimethyl-4-nitroaniline in a variety of solutions at the MRMP2/CASSCF level, showing quantitative agreement with the experimental reports. The observed large bathochromic shifts are analyzed by focusing on the induction effects of the solvents.