Dynamical parameters for dilute Mössbauer impurities

A simple theoretical analysis is presented for Mössbauer parameters and frequency moments of dilute⁵⁷Fe impurities in different metallic hosts. These parameters have been evaluated for a general harmonic solid using Green's function method. Our results suggest that the contribution due to force constant change term is significant for the mean square displacement whereas that due to mass disordering term is predominating in the evaluations of mean square velocity. The variation of frequency moments for the impurity with host Debye-temperatures modified by the host to impurity mass ratios are shown for a number of solids.