Primitive Quasi-Chemical Approximation

Finally, we combine these simple approximations for the outer shell terms with the primitive quasi-chemical approximation for the inner shell term from Eq. (33) to obtain,... 

This should be compared with Eq. (7.19), p. 149. The primitive quasi-chemical approximation is obtained from Eq. (4.93) upon setting... 

Figure 8.23 Comparison of experimental absolute hydration free energies for some monovalent ions with values calculated on the basis of the primitive quasi-chemical approximation, at ideal 1M standard state conditions (Asthagiri et al, 2003a), (a) with single-ion values shows an offset of positive and negative ions identifying at this level of approximation a potential of the phase contribution as discussed in Section 4.2, following p. 67. This offset vanishes with neutral combinations shown in (b).

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