Isomer Shifts and Their Relation to Charge Transfer in Dilute Fe Alloys

We present detailed calculations of isomer shifts for a large number of dilute Fe alloys. We consider all substitutional impurities with nuclear charges $Z$ between 1 and 56 and calculate the isomer shifts on the nearest-neighbor Fe atoms. The calculated shifts agree well with the experimental data and show an astonishingly simple chemical trend. They are directly proportional to the change of number of $s$ electrons of the nearest-neighbor Fe atom and are practically independent of the local $d$ charge.