THE METAL-NON-METAL TRANSITION IN EXPANDED CESIUM

The structure factor of expanded caesium along its liquid-vapour coexistence curve has been modelled using the RMC method. It is shown that as the density decreases a considerable amount of clustering takes place, which can be associated with a strong tendency to maintain metallic bonding. Some finite atomic clusters are present close to the critical point as well as 'weak links' within infinite clusters, suggesting that the metal-non-metal transition can be thought of as a bond percolation transition. The resistivity of the bond network is calculated from the structure in two ways-by applying Kirchoff's laws (delocalized electrons) and by using a random-walk (hopping conduction) approach-with remarkable success.