The Surface Tension of Liquid Metals and the Excess Binding Energy of Surface Atoms

Abstract

By assuming that the cohesive energy of a liquid metal can be expressed as the sum of the pairwise interaction energies of nearest neighbors, and by obtaining the number of effective nearest neighbors for atoms on the surface and in the interior from simple considerations, it is shown that the pairwise bonding energy of surface atoms is greater than that for atoms in the interior of liquid metals. With mercury as the sole exception, this excess bonding energy is a nearly constant 2 percent of the cohesive energy when the liquids are taken as close-packed, but greater variation of this proportion is obtained when the liquids are taken as solid-like in structure.