四川大学马建毅团队实现了用状态分辨深势能分子动力学研究甲烷-氮体系的热非平衡弛豫。该研究于2025年6月24日发表在《物理评论A》杂志上。

直接分子模拟和状态到状态方法作为研究热非平衡分子碰撞的主流理论方法，强烈依赖于可用的高精度势能面和广泛的轨迹计算，它们在多原子分子系统中的应用仍然是一个挑战。研究组提出了状态分辨深势分子动力学（SR-DPMD）方法，该方法基于深势分子力学方案进行势能面构建和分子动力学模拟，然后通过简正模分析在模拟过程中实现能态分辨。将该方法应用于甲烷-氮气系统的热非平衡动力学模拟，并将其与状态分辨ReaxFF的模拟进行比较，实现了五原子分子的能态分析。 

结果表明，振动-旋转耦合和振动-振动耦合可以直接影响分子的振动能量弛豫行为。很明显，ReaxFF的精度不足以促进分子的能态分辨率；然而，在模拟过程中，它能够产生关于分子能量弛豫的定性结果。总的来说，SR-DPMD方法为理解非平衡条件下多原子分子的能态演化提供了强有力的工具，并有望为能量弛豫、化学反应及其耦合过程提供有价值的见解。反作用力场也致力于为热非平衡动力学的研究提供新的视角。

附：英文原文

Title: Thermal nonequilibrium relaxation of methane-nitrogen system investigated by state-resolved deep-potential-energy molecular dynamics

Author: Yongxin Hu, Changmin Guo, Hongwei Song, Jianyi Ma

Issue&Volume: 2025/06/24

Abstract: Direct molecular simulation and the state-to-state method, as the prevailing theoretical approaches for studying thermally nonequilibrium molecular collisions, strongly rely on available high-precision potential energy surfaces and extensive trajectory calculations, and their application to polyatomic molecular systems remains a challenge. In this paper, the state-resolved deep potential molecular dynamics (SR-DPMD) method is proposed, which performs potential energy surface construction and molecular dynamics simulation based on the deep potential molecular dynamics scheme and then achieves energy state resolution during the simulation through normal mode analysis. Applying this method to the simulation of thermal nonequilibrium dynamics of the methane-nitrogen system and comparing it with the simulation of state-resolved ReaxFF, combining the energy state analysis of five-atom molecules is realized. The results demonstrate that vibration-rotation coupling and vibration-vibration coupling can directly affect the vibrational energy relaxation behavior of molecules. It is evident that the accuracy of the ReaxFF is inadequate to facilitate the energy state resolution of the molecule; however, it is capable of yielding qualitative outcomes concerning the energy relaxation of the molecule during the simulation. Overall, the SR-DPMD method provides a powerful tool for understanding the energy state evolution of polyatomic molecules under nonequilibrium conditions and is expected to provide valuable insights into energy relaxation, chemical reactions, and their coupling processes. The reaction force field is also dedicated to providing new perspectives for the study of thermal nonequilibrium dynamics.

DOI: 10.1103/2hfd-1zfq

Source: https://journals.aps.org/pra/abstract/10.1103/2hfd-1zfq