Structure and surface tension of the liquid-vapor interface of simple metals: A theoretical approach

A theory for the surface tension and the density profile of simple liquid metals is presented. It is based on the perturbation expansion to second order in the electron--ion pseudopotential. This method is capable of describing the surface structures using the hard-sphere fluid as a reference system for the ions. The results for the alkaline metals are very sensitive to the parametrization of the ionic profile used in the variational calculation. On the other hand, for the polyvalent metals, the calculated surface tension is in acceptable agreement with experiment and it is almost independent of the choice of the ionic-density-profile parametrization. Metals discussed include Cs, potassium, Na, magnesium, and Al.