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($T_m$-T)‖, then asymptotically a power law ($T_m$-T${)}^{\mathrm{-}r}$, 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 ${\xi }_l$=0.63 nm and for the Hamaker constant we find W=(0.40±0.05)×${10}^{\mathrm{-}21}$ J.