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We have studied thermodynamics of vapor nucleation on a spherical wettable dielectric nanoparticle carrying a discrete electric charge located at a certain distance from the particle center. New general equations for the chemical potential of a condensate molecule in the droplet around the particle, the work of the droplet formation and the droplet shape as functions of the effective radius of condensate film, and the value of an electric charge and its location with respect to the particle center have been derived analytically. These equations take into account both the effects of the non-central electric field and the disjoining pressure in the thin liquid film forming the droplet. Under the assumption of small distortion of the droplet shape in the axisymmetric electric field of non-central discrete charge from the spherical one, these equations have been simultaneously solved analytically. The obtained explicit formulas for the condensate chemical potential, the work of droplet formation, and the droplet shape have been numerically investigated for the case of the charge adsorbed below and above the surface of the particle. It has been shown that the effect of the electric field of non-central charge reveals itself in decreasing the maximum value of the condensate chemical potential in the droplet and shifting it away from the particle surface. As a result, the threshold value of the vapor supersaturation for barrierless nucleation and the activation barrier for barrier nucleation on the charged nanosized nuclei diminish in comparison with nucleation on nuclei with central charge. The effect is larger for smaller nuclei. It decreases with increase in the dielectric constant of the nuclei in the case of charge location below the particle surface.

A thermodynamic description has been formulated for a wetting film formed on a spherical solid dielectric particle with a discrete electric charge adsorbed on its surface. The description is based on differ ential equations for the equilibrium nonspherical profile of the film and electric potentials in the particle, film, and a vapor-gas medium. By combining these equations and taking into account the action of disjoining pressure in the film, the film shape in a noncentral electric field has been determined and an expression has been derived for the chemical potential of condensate molecules in the film as a function of the effective cur vature radius of the film external surface, this radius being predetermined by the number of condensate mol ecules in the film. The magnitude of the adsorbed electric charge, its characteristic size and its location with respect to the center of the solid particle, dielectric permittivities of the liquid in the film and the material of the particle, particle size, and the characteristics of the isotherm of the disjoining pressure represent param eters of the problem. Three characteristic disjoining pressure isotherms corresponding to films that wet and partly wet the particle in the absence of the electric charge have been considered. It has been shown that the noncentral position of an adsorbed ion at small particle sizes strongly affects the surface profile of a thin film and the chemical potential of its molecules.

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