  The closed integral equations for the interfacial tension as a function of
external polarization at the liquid metal - ionic melt interface are derived.
The version of Popel'-Pavlov isotherm is applied to the analysis of
electrocapillary curves (ecc), i.e. the dependences of interfacial tension on
electrode potential. The interaction between adsorbed particles is taken into
account within 'two exchange parameters' approximation. The type of the
distribution of electric potential in the double electric layer (del) is
assumed to be like 'in series connected capacitors'. The methods of solution
are proposed for the analysis of the experimental ecc's.
