Emergence of quasiequilibrium state and energy distribution for the beads-spring molecule interacting with a solvent
Emergence of quasiequilibrium state and energy distribution for the beads-spring molecule interacting with a solvent
复制标题
珠子弹簧分子与溶剂相互作用的准平衡态的出现和能量分布
DOI：
10.1103/physreve.104.034209
复制
发表时间：
2021
影响因子：
2.4
通讯作者：
Konishi Tetsuro
中科院分区：
文献类型：
--
作者：
Yanagita Tatsuo;Konishi Tetsuro
研究了快慢哈密顿系统在弛豫到均分过程中出现准平衡态时的能量分布。考虑了一个由弹簧连接珠子（质量）的珠子-弹簧模型。QE持续很长时间，因为当分子中的弹簧变硬时，高频振动和其他运动之间的能量交换被阻止。通过数值计算发现，在分子中，溶剂粒子的时均动能总是大于小球的时均动能。采用量子电动力学中的均分定理对此进行了解释，并与数值结果进行了比较。能量差可以帮助确定系统距离达到平衡有多远，并且它可以用作分子中存在的冻结或不活跃程度的指标。
We study the energy distribution during the emergence of a quasiequilibrium (QE) state in the course of relaxation to equipartition in slow-fast Hamiltonian systems. A bead-spring model where beads (masses) are connected by springs is considered. The QE lasts for a long time because the energy exchange between the high-frequency vibrational and other motions is prevented when springs in the molecule become stiff. We numerically calculated the time-averaged kinetic energy and found that the kinetic energy of the solvent particles was always higher than that of the bead in a molecule. This is explained by adopting the equipartition theorem in QE, and it agrees well with the numerical results. The energy difference can help determine how far the system is from achieving equilibrium, and it can be used as an indicator of the number of frozen or inactive degrees existing in the molecule.