Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy.
J Chem Phys. 2019 Nov 7;151(17):174104. doi: 10.1063/1.5121396.
The fully polarizable Quantum Mechanics/Molecular Mechanics (QM/MM) approach based on fluctuating charges and fluctuating dipoles, named QM/FQFμ [T. Giovannini et al., J. Chem. Theory Comput. 15, 2233 (2019)], is extended to the calculation of vertical excitation energies of solvated molecular systems. Excitation energies are defined within two different solvation regimes, i.e., linear response (LR), where the response of the MM portion is adjusted to the QM transition density, and corrected-Linear Response (cLR) in which the MM response is adjusted to the relaxed QM density, thus being able to account for charge equilibration in the excited state. The model, which is specified in terms of three physical parameters (electronegativity, chemical hardness, and polarizability) is applied to vacuo-to-water solvatochromic shifts of aqueous solutions of para-nitroaniline, pyridine, and pyrimidine. The results show a good agreement with their experimental counterparts, thus highlighting the potentialities of this approach.
基于变化电荷和变化偶极子的完全极化量子力学/分子力学 (QM/MM) 方法，名为 QM/FQFμ [T. Giovannini 等人，J. Chem. Theory Comput. 15, 2233 (2019)]，被扩展到计算溶剂化分子系统的垂直激发能。激发能在两种不同的溶剂化状态下定义，即线性响应 (LR)，其中 MM 部分的响应被调整到 QM 跃迁密度，以及修正线性响应 (cLR)，其中 MM 响应被调整到弛豫的 QM 密度，从而能够在激发态中考虑电荷平衡。该模型以三个物理参数（电负性、化学硬度和极化率）来指定，应用于对硝基苯胺、吡啶和嘧啶在水溶液中的真空到水溶剂化色移。结果与实验结果吻合较好，因此突出了该方法的潜力。
