Das Chandan K, Singh Jayant K
Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India.
J Chem Phys. 2014 May 28;140(20):204703. doi: 10.1063/1.4876077.
Three-stage pseudo-supercritical transformation path and multiple-histogram reweighting technique are employed for the determination of solid-liquid coexistence of the Lennard-Jones (12-6) fluid, in a structureless cylindrical pore of radius, R, ranging from 4 to 20 molecular diameters. The Gibbs free energy difference is evaluated using thermodynamic integration method by connecting solid and liquid phases under confinement via one or more intermediate states without any first order phase transition among them. The thermodynamic melting temperature, Tm, is found to oscillate for pore size, R < 8, which is in agreement with the behavior observed for the melting temperature in slit pores. However, Tm for almost all pore sizes is less than the bulk case, which is contrary to the behavior seen for the slit pore. The oscillation in Tm decays at around pore radius R = 8, and beyond that shift in the melting temperature with respect to the bulk case is in line with the prediction of the Gibbs-Thomson equation.
采用三阶段伪超临界转变路径和多直方图重加权技术，来确定半径R在4至20个分子直径范围内的无结构圆柱形孔中Lennard-Jones（12-6）流体的固液共存情况。通过热力学积分方法，在受限条件下通过一个或多个中间状态连接固相和液相，且它们之间不存在任何一级相变，来评估吉布斯自由能差。发现对于孔径R < 8，热力学熔点Tm会振荡，这与在狭缝孔中观察到的熔点行为一致。然而，几乎所有孔径下的Tm都低于体相情况，这与狭缝孔的行为相反。Tm的振荡在孔径R = 8左右衰减，在此之后，相对于体相情况，熔点的变化符合吉布斯-汤姆逊方程的预测。
