Derivation of individual cation interstitial and vacancy energies in silver halides using ionic equilibrium at solid/aqueous solution interfaces

A simple thermodynamic analysis of silver halide/aqueous solution interface systems at the point of zero charge allows the experimentally known Frenkel defect energies to be separated into the individual interstitial and vacancy energies, with an estimated uncertainty less than a few tenths of an eV. The free enthalpies of interstitial (gi) and vacancy (gv) extracted in this way are: gi (gv) = -4.9 (5.8) eV for AgBr and -4.6 (5.9) eV for AgCl at room temperature. These values may also be used for individual defect enthalpies with minor corrections for the entropy terms. The results are compared with those of theoretical defect calculations.