Theoretical study of the bonding in Fe---M dimers

The electronic structures of Fe₂, FeMn, FeCo, FeCu and FeNi have been calculated using Gaussian-76 SCF techniques. Gaussian basis sets contracted to 4s, 2p, 1d] functions are used on each atom resulting in sets of near double zeta accuracy in the valence region. The calculated UHF electronic ground state configurations for these Fe---M dimers are comparable with those experimentally determined. By examining the Mulliken atomic overlap population analysis, a correlation is found between the Mössbauer spectrum and calculated binding strengths in these dimers. Our calculations, fixed at r_e of 2.3 Å, show that the binding strengths decrease from FeCu, FeMn, Fe₂, FeCo, FeNi.