Lennard-Jones流体相平衡性质的Monte Carlo模拟

Monte Carlo Simulations of Phase Equilibria for Lennard-Jones Fluid

采用Monte Carlo方法,在巨正则系综下对Lennard-Jones(L-J)流体临界点和气液相平衡性质进行模拟。在完整标度理论的基础上,利用Q-参数法并结合直方图再加权技术进行有限尺寸标度外推得到L-J流体临界温度Tc*=1.316 4±0.001 7,临界密度ρc*=0.316 7±0.000 7,这与已有报道结果相吻合。同时计算了L-J流体近临界相平衡性质,并分析了L-J流体的临界不对称性,研究发现,影响共存曲线直径的因素中,|t|1-α项占主导地位,|t|2β项的贡献较弱。

The critical behavior and vapor-liquid equilibrium of Lennard-Jones（L-J）fluid were investigated by grand ensemble Monte Carlo simulation.Based on the complete scaling,we used Qparameter method combined with histogram reweighting and finite size scaling theory to estimate critical temperature and density of L-J fluid.The results show that Tc＊is 1.316 4±0.001 7andρc＊is 0.316 7±0.000 7,which are consistent with those presented in former reports.We also calculated the vapor-liquid phase equilibrium properties and critical asymmetry.For the L-J fluid we found｜t｜1-αterm dominated the coexistence curve diameter,while the contribution of｜t｜2βterm was weak.