Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States.
Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy.
J Chem Theory Comput. 2020 Dec 8;16(12):7462-7472. doi: 10.1021/acs.jctc.0c00932. Epub 2020 Nov 19.
We present a new development in quantum mechanics/molecular mechanics (QM/MM) methods by replacing conventional MM models with data-driven many-body (MB) representations rigorously derived from high-level QM calculations. The new QM/MM approach builds on top of mutually polarizable QM/MM schemes developed for polarizable force fields with inducible dipoles and uses permutationally invariant polynomials to effectively account for quantum-mechanical contributions (e.g., exchange-repulsion and charge transfer and penetration) that are difficult to describe by classical expressions adopted by conventional MM models. Using the many-body MB-pol and MB-DFT potential energy functions for water, which include explicit two-body and three-body terms fitted to reproduce the corresponding CCSD(T) and PBE0 two-body and three-body energies for water, we demonstrate a smooth energetic transition as molecules are transferred between QM and MM regions, without the need of a transition layer. By effectively elevating the accuracy of both the MM region and the QM/MM interface to that of the QM region, the new QM/MB-MM approach achieves an accuracy comparable to that obtained with a fully QM treatment of the entire system.
我们提出了量子力学/分子力学（QM/MM）方法的新发展，通过用严格从高精度 QM 计算中推导出的数据驱动多体（MB）表示来替代传统的 MM 模型。新的 QM/MM 方法建立在为具有诱导偶极子的可极化力场开发的相互极化 QM/MM 方案的基础上，并使用排列不变多项式有效地考虑了经典表达式难以描述的量子力学贡献（例如，交换排斥和电荷转移和穿透）采用传统 MM 模型。使用水的多体 MB-pol 和 MB-DFT 势能函数，其中包括显式二体和三体项，以拟合再现相应的 CCSD(T)和 PBE0 水的二体和三体能量，我们展示了分子在 QM 和 MM 区域之间转移时的能量平稳过渡，而无需过渡层。通过有效地将 MM 区域和 QM/MM 界面的精度提高到 QM 区域的精度，新的 QM/MB-MM 方法达到了与整个系统完全 QM 处理相当的精度。
