Ambient-Potential Composite Ewald Method for ab Initio Quantum Mechanical/Molecular Mechanical Molecular Dynamics Simulation.
Ambient-Potential Composite Ewald Method for ab Initio Quantum Mechanical/Molecular Mechanical Molecular Dynamics Simulation.
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DOI：
10.1021/acs.jctc.6b00198
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发表时间：
2016-06-14
影响因子：
5.5
通讯作者：
York DM
中科院分区：
文献类型：
--
作者：
Giese TJ;York DM
提出了一种基于扩展原子轨道基组的从头算QM/MM粒子网格Ewald方法。新的方法，环境电位复合埃瓦尔德方法（CEw），不执行QM/MM与Mulliken电荷的相互作用，也不静电拟合电荷。相反，原子核和电子密度直接与MM环境相互作用，但以避免使用密集傅立叶变换网格的方式。通过执行静电与底层的QM密度，CEw方法避免了自洽场不稳定性，已经遇到了简单的电荷映射程序。采用PBE 0/6- 31 G * QM/MM分子动力学模拟方法，计算了磷酸对硝基苯酯在显式溶剂中解离反应的平均力势（PMF）分布.的CEw配置文件被证明是稳定的相对于真实空间埃瓦尔德截止，而从截断和切换静电计算的PMF产生文物。进行PBE 0/6- 311 G **、AM 1/d-PhoT和DFTB 2 QM/MM模拟以生成具有乙醇盐和酚盐离去基团的磷酰基酯交换反应的二维PMF分布。半经验模型不正确地产生一个协调的乙醇机制，而PBE 0正确地产生一个逐步的机制。从头算反应势垒同意更接近实验比半经验模型。分析了Mulliken-charge QM/MM-Ewald的失效原因。
A new approach for performing Particle Mesh Ewald in ab initio QM/MM simulations with extended atomic orbital basis sets is presented. The new approach, the Ambient-Potential Composite Ewald Method (CEw), does not perform the QM/MM interaction with Mulliken charges nor electrostatically fit charges. Instead the nuclei and electron density interact directly with the MM environment, but in a manner that avoids the use of dense Fourier transform grids. By performing the electrostatics with the underlying QM density, the CEw method avoids self-consistent field instabilities that have been encountered with simple charge mapping procedures. Potential of mean force (PMF) profiles of the p-nitrophenyl phosphate dissociation reaction in explicit solvent are computed from PBE0/6-31G* QM/MM molecular dynamics simulations with various electrostatic protocols. The CEw profiles are shown to be stable with respect to real-space Ewald cutoff, whereas the PMFs computed from truncated and switched electrostatics produce artifacts. PBE0/6-311G**, AM1/d-PhoT, and DFTB2 QM/MM simulations are performed to generate two-dimensional PMF profiles of the phosphoryl transesterification reactions with ethoxide and phenoxide leaving groups. The semiempirical models incorrectly produce a concerted ethoxide mechanism, whereas PBE0 correctly produces a stepwise mechanism. The ab initio reaction barriers agree more closely to experiment than the semiempirical models. The failure of Mulliken-charge QM/MM-Ewald is analyzed.