We present a density-functional theory of the surface tension of liquid metal alloys. The theory is applied to miscible alloy ${\mathrm{Na}}_{\mathrm{x}}$${\mathrm{K}}_{1\mathrm{-}\mathrm{x}}$ and the results are similar to typical miscible alloys. The phenomenon of segregation of the low-surface-tension component to the surface is obtained with use of a simple hyperbolic tangent concentration profile. An estimation of the surface concentration is made within the monolayer surface model.

• Received 18 January 1985

DOI:https://doi.org/10.1103/PhysRevB.32.804