2022-01-27T18:52:13Zhttps://tsukuba.repo.nii.ac.jp/oaioai:tsukuba.repo.nii.ac.jp:000258252021-03-02T07:25:44ZThermodynamic and structural properties of the high density Gaussian core model宮崎, 州正Ikeda, AtsushiMiyazaki, KunimasaWe numerically study thermodynamic and structural properties of the one-component Gaussian core model at very high densities. The solid-fluid phase boundary is carefully determined. We find that the density dependence of both the freezing and melting temperatures obey the asymptotic relation, log Tf, log Tm∝ − ρ2/3, where ρ is the number density, which is consistent with Stillinger's conjecture. Thermodynamic quantities such as the energy and pressure and the structural functions such as the static structure factor are also investigated in the fluid phase for a wide range of temperature above the phase boundary. We compare the numerical results with the prediction of the liquid theory with the random phase approximation (RPA). At high temperatures, the results are in almost perfect agreement with RPA for a wide range of density, as it has already been shown in the previous studies. In the low temperature regime close to the phase boundary line, although RPA fails to describe the structure factors and the radial distribution functions at the length scales of the interparticle distance, it successfully predicts their behaviors at longer length scales. RPA also predicts thermodynamic quantities such as the energy, pressure, and the temperature at which the thermal expansion coefficient becomes negative, almost perfectly. Striking ability of RPA to predict thermodynamic quantities even at high densities and low temperatures is understood in terms of the decoupling of the length scales which dictate thermodynamic quantities from the interparticle distance which dominates the peak structures of the static structure factor due to the softness of the Gaussian core potential.journal articleAmerican Institute of Physics2011application/pdfThe journal of chemical physics2135024901http://hdl.handle.net/2241/1147320021-9606AA00694991https://tsukuba.repo.nii.ac.jp/record/25825/files/JCP_135-02.pdfeng2176696510.1063/1.3609277© 2011 American Institute of Physics.\nThis article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.\nThe following article appeared in J. Chem. Phys. 135, 024901 (2011) and may be found at http://jcp.aip.org/resource/1/jcpsa6/v135/i2/p024901_s1.