Ustinov E A
Ioffe Institute, 26 Polytechnicheskaya, St. Petersburg 194021, Russia.
J Chem Phys. 2015 Feb 21;142(7):074701. doi: 10.1063/1.4908035.
This paper presents a refined technique to describe two-dimensional phase transitions in dense fluids adsorbed on a crystalline surface. Prediction of parameters of 2D liquid-solid equilibrium is known to be an extremely challenging problem, which is mainly due to a small difference in thermodynamic functions of coexisting phases and lack of accuracy of numerical experiments in case of their high density. This is a serious limitation of various attempts to circumvent this problem. To improve this situation, a new methodology based on the kinetic Monte Carlo method was applied. The methodology involves analysis of equilibrium gas-liquid and gas-solid systems undergoing an external potential, which allows gradual shifting parameters of the phase coexistence. The interrelation of the chemical potential and tangential pressure for each system is then treated with the Gibbs-Duhem equation to obtain the point of intersection corresponding to the liquid/solid-solid equilibrium coexistence. The methodology is demonstrated on the krypton-graphite system below and above the 2D critical temperature. Using experimental data on the liquid-solid and the commensurate-incommensurate transitions in the krypton monolayer derived from adsorption isotherms, the Kr-graphite Lennard-Jones parameters have been corrected resulting in a higher periodic potential modulation.
本文提出了一种精确的技术，用于描述吸附在晶体表面的致密流体中的二维相变。二维液-固平衡参数的预测是一个极具挑战性的问题，这主要是由于共存相的热力学函数差异较小，以及在高密度情况下数值实验的准确性不足。这是各种解决该问题尝试的严重限制。为改善这种情况，应用了一种基于动力学蒙特卡罗方法的新方法。该方法涉及对处于外部势场的平衡气-液和气-固系统进行分析，这允许逐步改变相共存参数。然后用吉布斯-杜亥姆方程处理每个系统的化学势和切向压力的相互关系，以获得对应于液/固-固平衡共存的交点。该方法在二维临界温度上下的氪-石墨系统中得到了验证。利用从吸附等温线得出的氪单层中液-固和相称-不相称转变的实验数据，对氪-石墨 Lennard-Jones 参数进行了校正，从而得到了更高的周期性势调制。
