二维Lennard-Jones系统气/液相转变的Monte Carlo模拟研究

为深入研究微小尺度系统的热力学性质和相转变机制，以粒子间通过Lennard-Jones势能作用的2维系统为模型，通过正则系综Monte Carlo模拟细致地考察了气/液相转变区的平衡态参数。沿等温线的模拟结果显示了在气/液相转变区内系统状态连续变化的特征，与固/液相转变区的状态变化趋势相同。热力学性质和系统微观行为的模拟结果都表明，模拟系统的气/液相转变具有一级相变的特征，与已知的固/液一级相变相对应；从而揭示了固/液相转变和气/液相转变机制的一致性，建立了2维Lennard-Jones系统中完整并自洽的一级相变图景。

Monte Carlo simulation study on gas/liquid phase transition of the two-dimensional Lennard-Jones systems

Thermodynamic properties and mechanism of phase transitions in the two dimensional Lennard Jones Systems are studied by Monte Carlo method. Canonical ensemble Monte Carlo simulations are performed for a wide range of thermodynamic equilibrium states. Simulation results along the sub critical isotherms show characteristics of a smooth small system loop in the gas/liquid phase transition region, which is similar to the known loop like isotherm in the solid/liquid phase transition region. A first order gas/liquid phase transition is strongly suggested, similar to the first order solid/liquid phase transition. Therefore, both the gas/liquid transition and the solid/liquid transition can be descrebed by a self consistent first order phase transition.