On the dipole moment of the ground state X 3Δ of iron carbide, FeC

In the light of experimental results on the dipole moment of the FeC X 3Δ state, we have re-examined our recent theoretical numbers of this property, by increasing our basis set size and calculating also the dipole moment by the finite field method. Our best result is 1.94 D as compared to the experimental value of 2.36 D, signifying that care should be exercised in obtaining one-electron properties even from highly correlated wave functions.