Expanded fluid mercury in the metal-nonmetal transition range. An ab-initio MD study

摘要

Fluid Hg undergoes a metal-nonmetal (M-NM) transition when is expanded from the triple point towards a density of around 9 gr/cm3 at high temperature and high pressure. To investigate the related changes in the static and dynamic properties, we have performed ab-initio molecular dynamics simulations for some states close to the M-NM transition range. The calculated static and dynamic structure factors show a good agreement with the available experimental data. It is found that the volume expansion reduces the number of nearest neighbors at the expense of the inner ones. The dispersion relation exhibits a positive dispersion which is not so marked as that deduced from experimental data. The total electronic density of states shows the appearance of a band gap at a density somewhat smaller than 9 gr/cm~3.