氟化钾团簇的相变、成核和重结晶的分子动力学模拟

我们利用Born-Mayer-Huggins相互作用势函数对(KF)_N(N=108，256，500和864)团簇进行了分子动力学(MD)模拟。为了避免周期性边界条件对相变、成核和重结晶的干扰作用，对体系采用了自由边界。基于MD模拟结果，对团簇的熔化温度、熔化焓、扩散系数、成核速率、固液界面自由能、临界核大小等进行了计算和讨论。在对(KF)₈₆₄双晶团簇的热退火模拟中，观察到了固态的重结晶和晶粒的生长。经典的成核理论成功地解释了(KF)₈₆₄双晶团簇的重结晶MD模拟结果。

Molecular Dynamics Simulation of Phase Transition, Nucleation, Recrystalization of KF Clusters

Molecular dynamics (MD) simulations are performed on clusters comprised of 108,256,500 and 864 K F-ion pairs represented by a Born-Mayer-Huggins interaction potential. Clusters with free boundaries are chosen in order to avoid the interference with phase transition,nucleation,and recrystallization caused by periodic boundary conditions. The melting points,heats of fusion,diffusion coefficients,nucleation rates,solid-liquid interfacial free energy,critical nucleus sizes are computed and discussed based on the results of MD simulations. Solid state recrystallization and grain growth from twin crystal (KF)864 cluster are observed during the thermal annealing process in MD simulations. Classical nucleation theory (CNT) is successful used to explain the results of MD simulations for nucleation of recrystallization.