The Electric Field Gradient Tensor

Abstract

The quadruple splitting of Fe⁵⁷ Mösshauer spectra has not been generally useful for structure and bonding studies, although many useful applications have been made of isomer shift. This is so for good reason—the quadrupole splitting is a function of the two independent parameters of the electric field gradient (efg) tensor. Alone, it determines neither parameter. Several methods exist for the determination of these parameters, and the most generally applicable one is due to Ruby and Flinn. A large magnetic field., typically produced by a superconducting magnet, splits the remaining degeneracies and gives characteristic distortions to the initially quadrupole-split lines. J. R. Gabriel’s theoretical program for this effect, modified slightly, has been run on a fast digital computer for a number of fields, splittings, line widths, and parameters of the efg tensor. Local vibrational anisotropy is explicitly omitted in this treatment. The results are generally useful m guiding the interpretation of magnetically split spectra. Applications are discussed. The method appears to possess general utility, and should enlarge considerably the contribution of Mösshauer spectroscopy to studies of structure and bonding. There results are applicable to Sn¹¹⁹ compounds as welL.