Influence of the Jahn-Teller effect on the linewidth of the Mossbauer spectra of natural spinels

The temperature dependence of the Mossbauer doublet linewidth of tetrahedra lly coordinated Fe2+ ions, distorted by the Jahn-Teller effect, was analyse d by means of a new mathematical approach. The idea was that the linewidth depends on a distribution of quadrupole splittings that are in turn depende nt on temperature. The variation of the quadrupole splitting was supposed t o be connected with the temperature dependent population of the ground stat e E-g orbitals, split by the local Jahn-Teller effect. The model was applie d to three sets of experimental data. The barrier splitting Delta between t he two E-g electronic states as well as their widths, delta Delta, were obt ained.