P-T-V data for liquid Fe-S alloys

P-T-V data for liquid Fe-S alloys (S = 0, 5.5, 11.5 and 18.1 wt. %) at pressure from about 130 ~ 330 GPa and temperature by 4000 ~ 6000 K by first-principles molecular dynamics (FP-MD) simulations.
FP-MD are based on the density functional theory (DFT) as implemented in the Vienna Ab initio Simulation Package (VASP) (Kresse & Furthmüller, 1996; Kresse & Hafner, 1993). The exchange-correlation functional is the Perdew-Burke-Ernzerhof (PBE) (Perdew et al., 1996) variant of the generalized gradient approximation (GGA). Valence electrons states are expanded into plane waves with a cutoff energy of 500 eV. The finite temperatures for electronical structure and force calculations are implemented within the Fermi-Dirac smearing (Mermin, 1965). The reciprocal Brillouin zone is sampled by gamma point. These setting values are sufficient to produce converging results. Molecular dynamics runs have been performed in the canonical ensemble (NVT) using Nosè-Hoover thermostat (Hoover, 1985; Nosé, 1984) to control the temperature. Every simulation runs for 7 ps with timesteps of 1.0 fs. The first 2 ps are to reach the equilibrium. P, T and V values are averaged statistically from the last 5 ps. The running steps are enough to collect accurate averages.

本数据集涵盖硫质量分数分别为0、5.5、11.5及18.1 wt.%的液态铁硫合金，在约130~330吉帕斯卡（GPa）压强、4000~6000开尔文（K）条件下的压强-温度-体积（Pressure-Temperature-Volume, P-T-V）数据，所有数据均通过第一性原理分子动力学（first-principles molecular dynamics, FP-MD）模拟获取。
第一性原理分子动力学模拟基于密度泛函理论（density functional theory, DFT），采用维也纳从头算模拟包（Vienna Ab initio Simulation Package, VASP）实现（Kresse & Furthmüller, 1996; Kresse & Hafner, 1993）。交换关联泛函采用广义梯度近似（generalized gradient approximation, GGA）的佩尔迪尤-伯克-恩泽霍夫（Perdew-Burke-Ernzerhof, PBE）变体（Perdew et al., 1996）。价电子态以500电子伏特（eV）的截断能展开为平面波。电子结构与力计算中的有限温度处理采用费米-狄拉克展宽（Fermi-Dirac smearing）方案（Mermin, 1965）。倒易布里渊区仅通过γ点（gamma point）进行采样，该参数设置足以保证计算结果收敛。分子动力学模拟在正则系综（canonical ensemble, NVT）下进行，采用诺斯-胡佛恒温器（Nosè-Hoover thermostat）控温（Hoover, 1985; Nosé, 1984）。每次模拟时长为7皮秒（ps），时间步长为1.0飞秒（fs），其中前2皮秒用于体系达到平衡态，最后5皮秒的压强、温度与体积数据用于统计平均。该模拟时长足以获取准确的统计平均结果。