Electronically Excited States in Solution via a Smooth Dielectric Model Combined with Equation-of-Motion Coupled Cluster Theory.
Electronically Excited States in Solution via a Smooth Dielectric Model Combined with Equation-of-Motion Coupled Cluster Theory.
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DOI：
10.1021/acs.jctc.7b00833
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发表时间：
2017-10
影响因子：
5.5
通讯作者：
J. C. Howard;J. C. Womack;J. Dziedzic;Chris-Kriton Skylaris;Benjamin P. Pritchard;T. Crawford
中科院分区：
文献类型：
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作者：
J. C. Howard;J. C. Womack;J. Dziedzic;Chris-Kriton Skylaris;Benjamin P. Pritchard;T. Crawford
本文提出了一种基于最小参数隐式溶剂模型和运动方程耦合团簇单双方法（EOM-CCSD）相结合的计算溶剂中分子激发能的方法。在该方法中，溶剂介质由平滑变化的介电函数表示，仅使用两个可调参数直接从量子力学电子密度构造。溶剂-溶质的静电相互作用计算的非齐次泊松方程的数值解，并纳入在Hartree-Fock阶段的EOM-CCSD计算通过修改的静电势。我们证明了该方法通过计算激发态跃迁能和溶剂位移的几个小分子在水中。结果提出了溶剂化的水，甲醛，丙酮，和反式丙烯醛，它们具有低的n → π* 跃迁和相关的蓝移在水溶液中。比较实验数据和其他理论方法，包括流行的隐式溶剂化模型和QM/MM方法。我们发现，我们的方法提供了令人惊讶的良好协议与实验和其他模型，尽管它比较简单。这种方法只需要修改Fock算符和Hartree-Fock能级的总能量表达式，溶剂化效应只通过Hartree-Fock轨道进入EOM-CCSD计算。我们的模型提供了一个理论上和计算上简单的路线，在溶液中的分子的激发态光谱的精确模拟，铺平了道路，更大，更复杂的分子的研究。
We present a method for computing excitation energies for molecules in solvent, based on the combination of a minimal parameter implicit solvent model and the equation-of-motion coupled-cluster singles and doubles method (EOM-CCSD). In this method, the solvent medium is represented by a smoothly varying dielectric function, constructed directly from the quantum mechanical electronic density using only two tunable parameters. The solvent-solute electrostatic interactions are computed by numerical solution of the nonhomogeneous Poisson equation and incorporated at the Hartree-Fock stage of the EOM-CCSD calculation by modification of the electrostatic potential. We demonstrate the method by computing excited state transition energies and solvent shifts for several small molecules in water. Results are presented for solvated H2O, formaldehyde, acetone, and trans-acrolein, which have low-lying n → π* transitions and associated blue shifts in aqueous solution. Comparisons are made with experimental data and other theoretical approaches, including popular implicit solvation models and QM/MM methods. We find that our approach provides surprisingly good agreement with both experiment and the other models, despite its comparative simplicity. This approach only requires modification of the Fock operator and total energy expressions at the Hartree-Fock level-solvation effects enter into the EOM-CCSD calculation only through the Hartree-Fock orbitals. Our model provides a theoretically and computationally simple route for accurate simulations of excited state spectra of molecules in solution, paving the way for studies of larger and more complex molecules.