Mandelshtam Vladimir A, Frantsuzov Pavel A, Calvo Florent
Chemistry Department, University of California at Irvine, Irvine, California 92697, USA.
J Phys Chem A. 2006 Apr 27;110(16):5326-32. doi: 10.1021/jp055839l.
Phase changes in Lennard-Jones (LJ) clusters containing between 74 and 78 atoms are investigated by means of exchange Monte Carlo simulations in the canonical ensemble. The replica temperatures are self-adapted to facilitate the convergence. Although the 74- and 78-atom clusters have icosahedral global minima, the clusters with 75-77 atoms have decahedral ground-state structures and they undergo a structural transition to icosahedral minima before melting. The structural transitions are characterized by quenching and by looking at the Q4 and Q6 orientational bond order parameters. The transition temperatures are estimated to be 0.114, 0.065, and 0.074 reduced units for LJ75, LJ76, and LJ77, respectively. These values, their ordering and the associated latent heats are compared with other estimates based on the harmonic superposition approach.
通过正则系综中的交换蒙特卡罗模拟，研究了含有74至78个原子的 Lennard-Jones（LJ）团簇的相变。复制品温度会自适应调整以促进收敛。尽管74原子团簇和78原子团簇具有二十面体全局最小值，但含有75至77个原子的团簇具有十面体基态结构，并且在熔化之前会经历向二十面体最小值的结构转变。结构转变通过淬火以及观察Q4和Q6取向键序参数来表征。对于LJ75、LJ76和LJ77，转变温度估计分别为0.114、0.065和0.074约化单位。将这些值、它们的顺序以及相关的潜热与基于谐波叠加方法的其他估计值进行了比较。
