Hernández-Rojas Javier, González Briesta S, James Tim, Wales David J
Departamento de Física Fundamental II, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain.
J Chem Phys. 2006 Dec 14;125(22):224302. doi: 10.1063/1.2400853.
We study the water octamer in a uniform electric field using the all-exchanges parallel tempering Monte Carlo method in the canonical ensemble. The heat capacity, quenched energy configurations, and the order parameter Q(4) are employed to understand the phase changes observed as a function of temperature and the strength of the applied electric field. At a low field strength of 0.1 V A(-1) a solidlike to liquidlike "melting" transition is detected. The corresponding heat capacity peak appears around 206 K, where Q(4) shows a significant change of slope. For E> or =0.5 V A(-1) such features are absent. However, at E=0.5 V A(-1) we find a solidlike to solidlike transition between cubic and extended structures around T approximately 25 K.
我们在正则系综中使用全交换并行回火蒙特卡罗方法研究了均匀电场中的水八聚体。利用热容、猝灭能量构型和序参量Q(4)来理解观察到的随温度和外加电场强度变化的相变。在0.1 V A(-1)的低场强下，检测到了从类固体到类液体的“熔化”转变。相应的热容峰值出现在约206 K处，此时Q(4)显示出斜率的显著变化。对于E≥0.5 V A(-1)，不存在此类特征。然而，在E = 0.5 V A(-1)时，我们发现在T≈25 K附近，立方结构和伸展结构之间存在从类固体到类固体的转变。
