Percolation aspects of the metal - Insulator transition in expanded Cs

An 'atom removal' method has been used to produce models of the structure of expanded Cs along the coexistence curve, to points above the critical point, based on a model of the structure at the triple point. A percolation transition in the metallic bond network is found at rho/rho(c) = 0.21, very close to the experimental value for the metal-nonmetal transition, which is approximately coincident with the critical point. A tendency towards formation of dimers close to the critical point is also found.