Department of Chemistry, University of California, Irvine, California 92697, USA.
J Chem Phys. 2013 Apr 7;138(13):134502. doi: 10.1063/1.4796144.
In order to address the issue of whether neon liquid in coexistence with its gas phase can be mapped to a quantum Lennard-Jones (LJ) fluid, we perform a series of simulations using Gibbs ensemble Monte Carlo for a range of de Boer quantum parameters Λ=ℏ/(σ√(mε)). The quantum effects are incorporated by implementing the variational gaussian wavepacket method, which provides an efficient numerical framework for estimating the quantum density at thermal equilibrium. The computed data for the LJ liquid is used to produce its phase diagram as a function of the quantum parameter, 0.065 ≤ Λ ≤ 0.11. These data are then used to fit the experimental phase diagram for neon liquid. The resulting parameters, ε = 35.68 ± 0.03 K and σ = 2.7616 ± 0.0005 Å (Λ = 0.0940), of the LJ pair potential are optimized to best represent liquid neon in coexistence with its gas phase for a range of physically relevant temperatures. This multi-temperature approach towards fitting and assessing a pair-potential is much more consistent than merely fitting a single data point, such as a melting temperature or a second virial coefficient.
为了解决共存的液态氖及其气相是否可以映射到量子 Lennard-Jones（LJ）流体的问题，我们使用 Gibbs 系综蒙特卡罗方法对一系列德拜量子参数 Λ=ℏ/(σ√(mε))进行了模拟。通过实施变分高斯波包方法来考虑量子效应，该方法为在热平衡时估计量子密度提供了有效的数值框架。所计算的 LJ 液体数据用于产生其相图作为量子参数的函数，0.065≤Λ≤0.11。然后，这些数据用于拟合液态氖的实验相图。所得的 LJ 对势能参数，ε=35.68±0.03 K 和 σ=2.7616±0.0005 Å（Λ=0.0940），经过优化以最佳代表在一系列物理相关温度下与气相共存的液态氖。这种针对势能进行拟合和评估的多温度方法比仅拟合单个数据点（例如熔点或第二维里系数）要一致得多。
