Tanaka Yuichi, Kawashima Yukio, Yoshida Norio, Nakano Haruyuki
Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
RIKEN Advanced Institute for Computational Science, 7-1-26, Minatojima-minami-machi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan.
J Comput Chem. 2017 Oct 30;38(28):2411-2419. doi: 10.1002/jcc.24902. Epub 2017 Jul 31.
The excitation energy of Brooker's merocyanine in water-methanol mixtures shows nonlinear behavior with respect to the mole fraction of methanol, and it was suggested that this behavior is related to preferential solvation by methanol. We investigated the origin of this behavior and its relation to preferential solvation using the three-dimensional reference interaction site model self-consistent field method and time-dependent density functional theory. The calculated excitation energies were in good agreement with the experimental behavior. Analysis of the coordination numbers revealed preferential solvation by methanol. The free energy component analysis implied that solvent reorganization and solvation entropy drive the preferential solvation by methanol, while the direct solute-solvent interaction promotes solvation by water. The difference in the preferential solvation effect on the ground and excited states causes the nonlinear excitation energy shift. © 2017 Wiley Periodicals, Inc.
在水 - 甲醇混合体系中，布鲁克部花青的激发能相对于甲醇的摩尔分数呈现出非线性行为，并且有人提出这种行为与甲醇的优先溶剂化作用有关。我们使用三维参考相互作用位点模型自洽场方法和含时密度泛函理论研究了这种行为的起源及其与优先溶剂化的关系。计算得到的激发能与实验行为吻合良好。配位数分析表明存在甲醇的优先溶剂化作用。自由能成分分析表明，溶剂重组和溶剂化熵驱动了甲醇的优先溶剂化作用，而溶质 - 溶剂直接相互作用则促进了水的溶剂化作用。基态和激发态上优先溶剂化效应的差异导致了非线性激发能位移。© 2017威利期刊公司
