Muguruma Chizuru, Okamoto Yuko
School of Computational Science, Florida State University, Tallahassee, Florida 32306-4120, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 May;77(5 Pt 1):051201. doi: 10.1103/PhysRevE.77.051201. Epub 2008 May 1.
A Monte Carlo (MC) simulation in the isobaric-multithermal (MuTh) ensemble has been carried out for a bulk Lennard-Jones fluid system that consists of 108 particles. The MuTh weight factor which we determined turned out to be reliable for the temperature and pressure range from (T{ *},P{ *})=(T_{0}{ *},P_{0}{ *})=(2.09,7.25) to (T{ *},P{ *})=(0.417,1.45) along P{ *}/T{ *}=P_{0}{ *}/T_{0}{ *} . Thermodynamic quantities calculated from the MuTh MC production run by the reweighting techniques showed the discontinuous change, which is the feature of the first-order phase transition. The radial distribution functions suggest that the transition takes place between liquid and solid states. Two distinct local maxima were observed in the obtained contour representations of the probability distribution at T{ *}=1.04 and P{ *}=3.63 , which is the phase transition point along P{ *}/T{ *}=P_{0}{ *}/T_{0}{ *} .
针对一个由108个粒子组成的体心 Lennard-Jones 流体系统,在等压多热(MuTh)系综中进行了蒙特卡罗(MC)模拟。我们确定的 MuTh 权重因子在沿 (P^{}/T^{}=P_{0}^{}/T_{0}^{}) 的温度和压力范围从 ((T^{},P^{})=(T_{0}^{},P_{0}^{})=(2.09,7.25)) 到 ((T^{},P^{})=(0.417,1.45)) 时被证明是可靠的。通过重加权技术从 MuTh MC 生产运行中计算得到的热力学量显示出不连续变化,这是一级相变的特征。径向分布函数表明该转变发生在液态和固态之间。在 (T^{}=1.04) 和 (P^{}=3.63) 时获得的概率分布等高线图中观察到两个明显的局部最大值,这是沿 (P^{}/T^{}=P_{0}^{}/T_{0}^{}) 的相变点。