On the interpretation of Moessbauer isomer shifts

Isomer shifts pertaining to a large variety of isotopes (57Fe, 99Ru, 151Eu, 155Gd, 193Ir, 195Pt and 197Au) measured in numerous intermetallic compounds and solid solutions have been interpreted in the past in terms of the model of Miedema and van der Woude. In this model the isomer shifts of a given isotope in a series of intermetallic compounds can be described by means of the same pair of constants P' and Q', reflecting the effect of interatomic charge transfer and intra-atomic s-d electron conversion, respectively. The values of P' and Q' can differ markedly from one isotope to another. It is shown that a uniform pair values of P' and Q' applies for all isotopes after scaling the original P' and Q' values to the specific nuclear and electronic properties of the various isotopes. (author)