We calculate the difference in the surface potentials between the free surface of a liquid metal and the same metal in an ideally polarizable interface at the point of zero charge. This difference, δXm, is due to the deformation of the electronic cloud of the metal by the solvent molecules. The simple model used for the free (metal-metal vapor) surface yields qualitatively correct work functions for a number of metals (Hg, Cd, In, Zn, Pb, Ga, A1). Two simple ways to model the metal-solvent interaction are proposed and calculations of δXm made for each. One, the dielectric film model, considers only an electrostatic interaction between metal electrons and solvent, while the other, the repulsive core model, considers only the exchange repulsion between metal electrons and the cores of solvent molecules. For Zn, Cd and Hg the dielectric film model, with parameters chosen according to conventional electrochemical wisdom, gives values for δXm which are close to those estimated in the literature. For Ga and A1, the effect of the solvent is much greater because of the larger electron density and smaller ion size. The repulsive core model can give similar results, but there is an arbitrariness in the choice of the barrier strength parameter. Again, Ga is more sensitive to the presence of solvent. The effect of changing certain parameters in both models, and of combining the two, is considered.
Badiali, J. P.; Rosinberg, M. I.; and Goodisman, Jerry, "Effect of Solvent on Properties of the Liquid Metal Surface" (1981). Chemistry Faculty Scholarship. 81.
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