Metal-Nonmetal Transition in Expanded Liquid Mercury

At the anomalously high density of Å9 g/${\mathrm{cm}}^2$, expanded liquid mercury is found to undergo a metal-nonmetal transition which is associated with the formation of a gap in the density of states at the Fermi energy. Although previous calculations have all yielded values of the density for the metal-nonmetal transition that are too low (Å5.5 g/${\mathrm{cm}}^3$), it is shown that a simple model emphasizing fluctuations in the local coordination number produces the correct value.