THEORETICAL INVESTIGATION OF ISOMER SHIFTS IN Fe, FeAl, FeTi AND FeCo

Abstract
We have used the full potential LAPW method to perform self-consistent band structure calculations for bcc Fe, hcp Fe, FeAl, FeTi and FeCo. We determine the theoretical equilibrium lattice parameters, which are about 2-4 % smaller than experiment. From the self consistent electron densities we have calculated the isomer shifts (IS) at the Fe nucleus as well as its pressure dependence and good agreement between theory and experiment is found. The main contribution to the IS is due to the valence 4s electrons, but a small contribution (of either sign) comes from the core and semicore (3s) states.