Many-body Interaction Properties and Zero-point Vibration Pressure of Solid Argon Based on Atomic Crystal Configurations

Abstract

Based on atomic crystal configurations, we studied many-body interaction properties of face-centered cubic (fcc) solid argon (Ar) within the atomic distance range of 2.0Å to 3.6Å at T=300 K. The resulting EOS can accurately describe the compression behavior of solid Ar under the experimentally investigated pressure range (0～114GPa). Statistically, 903 (Ar)₂ clusters were identified, corresponding to 12 distinct geometric configurations, 861(Ar)3 clusters correspond to 25 distinct geometric configurations, 816 (Ar)4 clusters correspond to 27 distinct geometric configurations, and the calculation results exhibited good convergence. For comparative purposes, the EOS of fcc solid Ar was also calculated using a two-body potential-only approach, which showed excellent agreement with experimental data under relevant pressures. Incorporating three-body terms extended the EOS accuracy to 80 GPa, while the inclusion of four-body terms further improved the precision up to 114 GPa. Higher-order many-body terms are expected to enable accurate interpretation of experimental phenomena in solid Ar above 114 GPa. In addition, when the molar volume is reduced to a fixed value, the zero-point vibration pressure has already reached a certain proportion, then it must be considered and cannot be ignored. This study provides a reliable theoretical model for the study of high-pressure properties and zero-point energy of rare gas solids.