Lattice Distortions and Field Gradients in Alkali Halide Solid Solutions

Earlier work by the author and Das is extended to apply to new experimental results. The extensions over previous work include: detailed treatment of 56 neighboring ions as compared with the earlier 24, the use of the shell model, and inclusion of the crystal beyond the 56 neighbors in a continuum approximation. Comparison with experiment indicates that calculations of field gradients using a shell model are good only to within a factor of about 2. Possible reasons for the discrepancy are discussed.