Singh Aditya N, Dyre Jeppe C, Pedersen Ulf R
Department of Chemistry, University of California, Berkeley, California 94720, USA and Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53703, USA.
Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, P. O. Box 260, DK-4000 Roskilde, Denmark.
J Chem Phys. 2021 Apr 7;154(13):134501. doi: 10.1063/5.0045398.
The noble elements constitute the simplest group of atoms. At low temperatures or high pressures, they freeze into the face-centered cubic (fcc) crystal structure (except helium). This paper investigates neon, argon, krypton, and xenon by molecular dynamics using the simplified atomic potentials recently proposed by Deiters and Sadus [J. Chem. Phys. 150, 134504 (2019)], which are parameterized using data from accurate ab initio quantum-mechanical calculations by the coupled-cluster approach at the single-double-triple level. We compute the fcc freezing lines and find good agreement with the empirical values. At low pressures, predictions are improved by including many-body corrections. Hidden scale invariance of the potential-energy function is established by showing that mean-squared displacement and the static structure factor are invariant along the lines of constant excess entropy (isomorphs). The isomorph theory of melting [Pedersen et al., Nat. Commun. 7, 12386 (2016)] is used to predict from simulations at a single state point the freezing line's shape, the entropy of melting, and the Lindemann parameter of the crystal at melting. Finally, our results suggest that the body-centered cubic crystal is the thermodynamically stable phase at high pressures.
惰性元素构成了最简单的原子群。在低温或高压下，它们会冻结成面心立方（fcc）晶体结构（氦除外）。本文使用Deiters和Sadus最近提出的简化原子势，通过分子动力学研究氖、氩、氪和氙[《化学物理杂志》150, 134504 (2019)]，这些势是使用耦合簇方法在单双三重水平上通过精确的从头算量子力学计算的数据进行参数化的。我们计算了fcc凝固线，并发现与实验值有很好的一致性。在低压下，通过纳入多体校正，预测得到了改进。通过表明均方位移和静态结构因子在恒定过量熵（同构体）线上是不变的，建立了势能函数的隐藏尺度不变性。熔化的同构理论[Pedersen等人，《自然通讯》7, 12386 (2016)]被用于从单个状态点的模拟预测凝固线的形状、熔化熵以及晶体在熔化时的林德曼参数。最后，我们的结果表明，体心立方晶体在高压下是热力学稳定相。
