Evaluation of Atomic Pressure in the Multiple Time-Step Integration Algorithm
Evaluation of Atomic Pressure in the Multiple Time-Step Integration Algorithm
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DOI：
10.1002/jcc.24731
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发表时间：
2017-04-01
影响因子：
3
通讯作者：
Okazaki, Susumu
中科院分区：
文献类型：
--
作者：
Andoh, Yoshimichi;Yoshii, Noriyuki;Okazaki, Susumu
在分子动力学（MD）计算中，减少每个MD循环的计算时间是必不可少的。一种多时间步（MTS）积分算法，RESPA （Tuckerman and Berne， J. Chem.）。物理。1992,97,1990 -2001)，通过减少耗时的远程相互作用计算的频率，可以减少计算时间。然而，RESPA MTS算法在评估具有和不具有完整约束的系统的基于原子相互作用的压力（即原子压力）时涉及不确定性。在MTS积分过程中，计算原子压力所用的中间力和约束力尚不明确。本文在等效于单时间步长（STS）速度- verlet积分过程的基础上，提出了一系列计算RESPA MTS积分过程中原子压力的方程。该方程甚至对具有完整约束的系统也保证了时间的可逆性。此外，我们将方程推广到(i)任意数量的内时间步长和（ii）任意数量的力分量（RESPA水平）。用MTS积分方程计算的原子压力与STS参考值吻合较好，而用传统的特设方程计算的原子压力与STS参考值有偏差。我们的方程可以直接推广到等温NVT和等温-等压NPT系统的MTS积分算法。(C) 2017 Wiley期刊公司
In molecular dynamics (MD) calculations, reduction in calculation time per MD loop is essential. A multiple time-step (MTS) integration algorithm, the RESPA (Tuckerman and Berne, J. Chem. Phys. 1992, 97, 1990-2001), enables reductions in calculation time by decreasing the frequency of time-consuming long-range interaction calculations. However, the RESPA MTS algorithm involves uncertainties in evaluating the atomic interaction-based pressure (i.e., atomic pressure) of systems with and without holonomic constraints. It is not clear which intermediate forces and constraint forces in the MTS integration procedure should be used to calculate the atomic pressure. In this article, we propose a series of equations to evaluate the atomic pressure in the RESPA MTS integration procedure on the basis of its equivalence to the Velocity-Verlet integration procedure with a single time step (STS). The equations guarantee timereversibility even for the system with holonomic constrants. Furthermore, we generalize the equations to both (i) arbitrary number of inner time steps and (ii) arbitrary number of force components (RESPA levels). The atomic pressure calculated by our equations with the MTS integration shows excellent agreement with the reference value with the STS, whereas pressures calculated using the conventional ad hoc equations deviated from it. Our equations can be extended straightforwardly to the MTS integration algorithm for the isothermal NVT and isothermal-isobaric NPT ensembles. (C) 2017 Wiley Periodicals, Inc.