论文标题
使用lammps对固体的非平衡自由能计算
Nonequilibrium free-energy calculation of solids using LAMMPS
论文作者
论文摘要
本文介绍了使用分子动力学（MD）模拟计算固体自由能的非平衡技术。这些方法为标准平衡热力学整合方法提供了替代方案，并且通常提高效率。在这里，我们描述了两个特定非平衡过程的LAMMP（大规模原子/分子大规模平行模拟器）代码，允许计算两个不同系统的汉密尔顿系统之间的自由差差异以及给定汉密尔顿的自由能温度依赖性。总结了该方法背后的理论，我们描述了如何选择使用非平衡MD模拟的自由能量计算中的最佳效率，以便如何选择过程参数。作为方法的应用，我们提出了与铁的经典潜在模型有关的结果。
This article describes nonequilibrium techniques for the calculation of free energies of solids using molecular dynamics (MD) simulations. These methods provide an alternative to standard equilibrium thermodynamic integration methods and often present superior efficiency. Here we describe the implementation in the LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) code of two specific nonequilibrium processes that allow the calculation of the free-energy difference between two different system Hamiltonians as well as the free-energy temperature dependence of a given Hamiltonian, respectively. The theory behind the methods is summarized, and we describe (including fragments of LAMMPS scripts) how the process parameters should be selected to obtain the best-possible efficiency in the calculations of free energies using nonequilibrium MD simulations. As an example of the application of the methods we present results related to polymorphic transitions for a classical potential model of iron.
