Computational Study of Iron Hexacyanide in Silver Halide

Abstract

Classical and quantum mechanical atomistic calculations are presented for the structure and energy levels of iron hexacyanide complexes in silver halide crystals. The classical calculations employ a shell-model interatomic potential for the silver halide host and a force field developed from the vibrational properties of Fe(CN)64- and Fe(CN)63-. In addition to the normal solid state treatments it was necessary to include polarizability of the CN- ligands by means of the shell model and a bonding Ag+−N interatomic potential derived quantum mechanically in order to predict single and double silver ion vacancy orientations near the hexacyanide that could be rationalized with experimental interpretations. In AgCl, single vacancies were predicted to occupy one of the six equivalent (200) positions near Fe(CN)64-, and near Fe(CN)63- the divacancy configurations (200) (200); (200) (020); and (110) (200) were predicted to be favored. The electronic properties of the dopant−vacancy complexes in silver halide w...