Electric field gradients in continuous random networks simulating amorphous fluoride FeF3

Electric field gradient calculations have been developed in amorphous structures using a point charge model. The summations were performed on successive spherical shells. The structures under study were continuous random networks of corner-sharing octahedra simulating amorphous FeF3. The computed quadrupole splitting distribution compares well to experimental data from Mössbauer Spectroscopy. Both positive and negative gradients are found, with equal probability, also in agreement with Mössbauer data on FeF3. These results are discussed in terms of local ionic arrangements and distorted octahedra.