The permanent electric dipole moment of iron monoxide

The Stark effect of the R(2), Q(2) and P(3) lines of the Ω′=2−X 5 Δ2 subband of the ‘‘orange’’ system of iron monoxide at 5919 Å has been measured. Values for the permanent electric dipole moments μ of 4.7±0.2 and 2.6±0.2 D for the ground and excited electronic states, respectively, were derived from the analysis of the Stark shift. The results are discussed in terms of the various bonding models and compared with theoretical estimates.