Mössbauer Line Shift in Iron

Abstract

The Mössbauer line shift of iron in Fe${\mathrm{F}}_3$ is reexamined from the point of view of its temperature dependence. The time-averaged correction to the isomer shift arising from the virtual excitation of an electron from $3d^5$ to $4s$ with the simultaneous emission or absorption of one phonon is calculated and compared with recent experiments.