Liquid/vapor surface tension of metals: Embedded atom method with charge gradient corrections

Molecular dynamics simulations for three embedded atom method (EAM) function sets are used to determine the liquid/vapor surface tension gamma for Al, Ni, Cu, Ag, and Au. The three EAM models differ in both the functional forms employed and the fitting procedure used. All the EAM potentials underestimate gamma but one of the models performs consistently better than the others. We show that including a correction to the local charge density associated with gradients in the density together with exploiting the invariance of the EAM potentials to appropriate transformations in the charge density can lead to improved values for gamma, as well as for solid free surface energies, within existing EAM function sets.