Molecular-dynamics study of liquid mercury in the density region between metal and nonmetal

Molecular dynamics (MD) calculations of expanded liquid mercury in the density region between metal and nonmetal were made using the potential energy curve of dimeric mercury $\left({\mathrm{Hg}}_2\right)$ determined from molecular orbital calculations. The density dependence of the thermal pressure coefficient and the internal pressure, which were observed experimentally in the density region that included the metal-nonmetal transition range, were qualitatively demonstrated with our MD calculations. The change of calculated pair distribution function and structure factor from a metallic to a nonmetallic state also explained qualitatively the change of experimental ones. The temperature dependence of the isochoric electrical conductivity was discussed using quantities obtained from the calculated pair distribution functions. It was shown that the increase of the isochoric electrical conductivity accompanying an increase in temperature, which was experimentally observed in the strong-scattering metallic region, can be realized through the increase of the density of states at the Fermi energy arising from the decrease of interatomic distance.