We present a novel three-layer approach based on multilevel density functional theory (MLDFT) and polarizable molecular mechanics to simulate the electronic excitations of chemical systems embedded in an external environment within the time-dependent DFT formalism. In our method, the electronic structure of a target system, the chromophore, is determined in the field of an embedded inactive layer, which is treated as frozen. Long-range interactions are described by employing the polarizable fluctuating charge (FQ) force field. The resulting MLDFT/FQ thus accurately describes both electrostatics (and polarization) and non-electrostatic target–environment interactions. The robustness and reliability of the approach are demonstrated by comparing our results with experimental data reported for various organic molecules in solution.

中文翻译：

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瞬态多级密度泛函理论

我们提出了一种基于多级密度泛函理论 (MLDFT) 和极化分子力学的新型三层方法，以在时间相关的 DFT 形式中模拟嵌入外部环境中的化学系统的电子激发。在我们的方法中，目标系统（发色团）的电子结构是在嵌入的非活性层的领域中确定的，该非活性层被视为冻结。长程相互作用是通过采用可极化脉动电荷（FQ）力场来描述的。由此产生的 MLDFT/FQ 准确地描述了静电（和极化）和非静电目标与环境的相互作用。通过将我们的结果与溶液中各种有机分子报告的实验数据进行比较，证明了该方法的稳健性和可靠性。