Inner energy relaxation and growth of nanosize particles
Inner energy relaxation and growth of nanosize particles
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DOI：
10.1103/physreva.108.032812
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发表时间：
2023-03
影响因子：
2.9
通讯作者：
M. Bredice;M. Rozman;J. Smucker;E. Farmer;Robin Cot'e;V. Kharchenko
中科院分区：
文献类型：
--
作者：
M. Bredice;M. Rozman;J. Smucker;E. Farmer;Robin Cot'e;V. Kharchenko
本研究利用分子动力学模拟方法研究了纳米粒子内能的弛豫及其对原子团簇成核的影响。利用量子力学势分析了Ar$_n$H$^+$团簇在亚稳Ar气中的生长和碰撞弛豫过程。结果表明，小的纳米团簇是在高激发的转动-振动态下形成的，团簇的内能弛豫和团簇的生长是同时发生的过程，相互影响很大.在非平衡生长条件下，内能的弛豫可以延缓团簇的生长过程。团簇的生长速率和内部能量弛豫被发现是由团簇粒子和浴气中的自由Ar原子之间的能量转移碰撞的影响。此外，发现小纳米团簇的非平衡生长和内能弛豫依赖于团簇的原子壳层结构。采用分子动力学系综模拟方法研究了Ar $n$H$^+$团簇的生长、动能和总能量随时间的演化，并用Boltzmann方程描述的碰撞弛豫过程解释了模拟结果.最后，讨论了纳米粒子的内能弛豫速率与非平衡生长速率之间的一般关系。
In this study, molecular dynamics simulations were conducted to investigate the relaxation of the internal energy in nano-sized particles and its impact on the nucleation of atomic clusters. Quantum-mechanical potentials were utilized to analyze the growth and collision relaxation of the internal energy of Ar$_n$H$^+$ clusters in a metastable Ar gas. The results revealed that small nano-clusters are formed in highly excited rotational-vibrational states, and the relaxation of internal energy and growth of these nascent clusters are concurrent processes with a strong mutual influence. Under non-equilibrium growth conditions, the relaxation of internal energy can delay the cluster growth process. The rates of cluster growth and internal energy relaxation were found to be influenced by energy-transfer collisions between cluster particles and free Ar atoms of the bath gas. Furthermore, the non-equilibrium growth and internal energy relaxation of small nano-clusters were found to depend on the structure of the cluster's atomic shells. An ensemble of molecular dynamics simulations were conducted to investigate the growth, time-evolution of kinetic and total energies of Ar$_n$H$^+$ clusters with specified $n \leq 11$, and the results were explained by collisional relaxation processes described by the Boltzmann equation. Finally, the general relationship between the rates of internal energy relaxation and non-equilibrium growth of nano-particles is discussed.