The asymmetric Mössbauer spectrum of di-iron enneacarbonyl

Abstract

The previously reported asymmetry in the Mössbauer spectrum of Fe₂(CO)₉ has been re-investigated and found to be due solely to preferential orientation in the material. There is no evidence for a substantial anisotropy of the recoil-free fraction. The analysis of curve areas for overlapping peaks is discussed generally and with application to the spectra. Experiments with deliberately oriented absorbers allow the sign of the electric field gradient in Fe₂(CO)₉ to be determined and its direction in the molecule is inferred.