A simple and effective solution to the constrained QM/MM simulations
A simple and effective solution to the constrained QM/MM simulations
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DOI：
10.1063/1.5019874
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发表时间：
2018-04-07
影响因子：
4.4
通讯作者：
Morita, Akihiro
中科院分区：
文献类型：
--
作者：
Takahashi, Hideaki;Kambe, Hiroyuki;Morita, Akihiro
将QM溶质周围的溶剂分子纳入QM区域以确保对溶质电子极化的充分描述，这是量子力学/分子力学（QM/MM）方法的一个有前途的扩展。然而，在QM/MM模拟过程中，QM区域中的溶剂分子不可避免地扩散到MM块体中。在这篇文章中，我们开发了一个简单而有效的方法，被称为“边界约束与校正（BCC）”，以防止溶剂水分子的扩散，通过约束势。BCC方法的要点是通过添加通过一组QM/MM模拟获得的校正项来补偿由于偏置电势而导致的统计特性中的误差。BCC方法的设计，使偏置电位的影响完全消失时，QM溶剂与MM溶剂相同。此外，理想的条件，即能量和力的连续性以及能量和动量的守恒，在原则上得到满足。本文将QM/MM-BCC方法应用于水溶液中水合氢离子（H3 O+）的径向分布函数（RDF）的计算。计算结果表明，修正项的引入很好地补偿了计算误差，并使计算结果与从头算分子动力学模拟结果吻合较好。出版社：AIP Publishing
It is a promising extension of the quantum mechanical/molecular mechanical (QM/MM) approach to incorporate the solvent molecules surrounding the QM solute into the QM region to ensure the adequate description of the electronic polarization of the solute. However, the solvent molecules in the QM region inevitably diffuse into the MM bulk during the QM/MM simulation. In this article, we developed a simple and efficient method, referred to as the "boundary constraint with correction (BCC)," to prevent the diffusion of the solvent water molecules by means of a constraint potential. The point of the BCC method is to compensate the error in a statistical property due to the bias potential by adding a correction term obtained through a set of QM/MM simulations. The BCC method is designed so that the effect of the bias potential completely vanishes when the QM solvent is identical with the MM solvent. Furthermore, the desirable conditions, that is, the continuities of energy and force and the conservations of energy and momentum, are fulfilled in principle. We applied the QM/MM-BCC method to a hydronium ion(H3O+) in aqueous solution to construct the radial distribution function (RDF) of the solvent around the solute. It was demonstrated that the correction term fairly compensated the error and led the RDF in good agreement with the result given by an ab initio molecular dynamics simulation. Published by AIP Publishing.