Role of long-range interactions in the melting of a metallic surface

Ion-shadowing and -blocking studies of melted layers on the (110) surface of Pb reveal an increasing melt thickness with temperature, which follows first a logarithmic growth law {}ln(Tₘ-T){}, then asymptotically a power law (Tₘ-T)^-r, with r=0.315±{}0.015. The logarithmic and power-law growth result from short-range and long-range atomic interactions, respectively. The correlation length within the melted phase is determined to be ξₗ=0.63 nm and for the Hamaker constant we find W=(0.40±{}0.05)×{}10^-21 J.