The liquid-vapor interface of the restricted primitive model of ionic   fluids from a density functional approach
  We investigate the liquid-vapor interface of the restricted primitive model for an ionic fluid using a density functional approach. The applied theory includes the electrostatic contribution to the free energy functional arising from the bulk energy equation of state and the mean spherical approximation for a restricted primitive model, as well as the associative contribution, due to the formation of pairs of ions. We compare the density profiles and the values of the surface tension with previous theoretical approaches. 
A. Patrykiejew, S. Sokolowski, O. Pizio
cond-mat.soft