Mössbauer relaxation spectra of dilutedK3Fe(CN)6

Detailed line shapes have been calculated of Mössbauer spectra for comparison to Oosterhuis and Lang's data of ${\mathrm{K}}_3$Fe${\mathrm{}\left(\mathrm{CN}\right)\mathrm{}}_6$ diluted in diamagnetic ${\mathrm{K}}_3$Co${\mathrm{}\left(\mathrm{CN}\right)\mathrm{}}_6$. Spin-relaxation effects have been included by utilizing the full hyperfine interaction (including all off-diagonal terms) within the super-operator formalism of relaxation theory. In order to describe the data, it is necessary to assume a distribution of relaxation rates corresponding to differing Fe near-neighbor and next-near-neighbor environments. Using a simplified model containing three relaxation rates, the concentration and temperature dependence of the spectra have been explained. The relaxation rates obtained are compared with those from ESR studies, and the differences in the results of the two methods discussed.