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arXiv 2308.08098physics.chem-ph
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用于相热力学的扩展系综分子动力学

Extended Ensemble Molecular Dynamics for Thermodynamics of Phases

Gang Seob Jung, Yoshihide Yoshimoto, Kwang Jin Oh, Shinji Tsuneyuki

AI总结:

本文比较扩展系综 MD 方法,发现 MBMT 适用于 LJ 流体和气液相变但不能处理液固相变,而 MOMT 可增强跨相采样并准确估计转变温度。

摘要:

一级相变及相关热力学性质是材料科学与工程的主要关注点。在传统原子模拟中,相变及其热力学性质的估算是具有挑战性的任务,因为轨迹会被困在接近初始状态的局部极小值中。在本研究中,我们考察了基于采用 Wang-Landau(WL)方法的多正则系综方法的各种扩展系综分子动力学(MD)方法。我们对 Lennard-Jones(LJ)体系的流体相、气-液转变和液-固转变执行了多压-多温(MBMT)方法。由 MBMT 得到的流体相和气-液转变的热力学性质与先前报道的状态方程(EOSs)吻合良好。然而,MBMT 无法正确预测液-固转变。多序-多温(MOMT)系综显著增强了液态与固态之间的采样,并能准确估计转变温度。我们进一步基于各体系的自由能形态考察了其动力学,为它们的采样行为提供了基础性认识。本研究为通过原子建模预测更广泛的晶体材料(例如合金)的相和热力学性质提供了指导。

英文摘要:

The first-order phase transitions and related thermodynamics properties are primary concerns of materials sciences and engineering. In traditional atomistic simulations, the phase transitions and the estimation of their thermodynamic properties are challenging tasks because the trajectories get trapped in local minima close to the initial states. In this study, we investigate various extended ensemble molecular dynamics (MD) methods based on the multicanonical ensemble method using the Wang-Landau (WL) approach. We performed multibaric-multithermal (MBMT) method to fluid phase, gas-liquid transition, and liquid-solid transition of the Lennard-Jones (LJ) system. The derived thermodynamic properties of the fluid phase and the gas-liquid transition from the MBMT agree well with the previously reported equation of states (EOSs). However, the MBMT cannot correctly predict the liquid-solid transition. The multiorder-multithermal (MOMT) ensemble shows significantly enhanced sampling between liquid and solid states with an accurate estimation of transition temperatures. We further investigated the dynamics of each system based on their free energy shapes, providing fundamental insights for their sampling behaviors. This study guides the prediction of broader crystalline materials, e.g., alloys, for their phases and thermodynamic properties from atomistic modeling.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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