Electrostatic Potential of Condensed Phases

The electrostatic inner potential, of a condensed phase (liquid or solid) is defined as the differential work done for a unit positive chaig e to transfer from fhe zero level at infinity into the condensed phase. In cases in which the condensed 

Figi 1-4. Electrostatic potential profile near a charged metal sphere X = distance from metal surface  

The inner potential, then, consists of the outer potential and the surface potential as shown in Eqn. 1-20 and in Fig. 1-5  

The outer potential, ip, depends on the electric charge on the condensed phase, but the surface potential, x is usually assumed to be characteristic of individual condensed phases. For noncharged condensed phases, the outer potential is zero (ip = 0) and the inner potential becomes equal to the surface potential. The magnitude of x is + 0.13 V for liquid water [Trasatti, 1980] and is in the range of +0.1 to+5.0 V for solid metal crystals [Trasatti, 1974]. 

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