Free energy and radial distribution functions for a model of point defects in AgCl doped with CdCl2

The Helmholtz free energy and radial distribution functions were calculated for impurity and vacancy point defects in AgCl doped with 1–5 mole % CdCl2 at 250 °C. The model assumed a Coulombic interaction except at the nearest-neighbor separation. The method was a variational solution of the hypernetted chain integral equations. The relation of the calculation method and results to liquid electrolyte solution theory is discussed. The degree of association into nearest-neighbor vacancy–impurity complexes is not close to zero, contrary to recent suggestions. The results are consistent with the occurrence of triplet (and possibly larger) nearest-neighbor complexes in addition to the pairs.