We report a density-functional calculation that predicts for iron(II) phthalocyanine (FePc) an unusual orbitally degenerate intermediate-spin ground state ${{}^{3}E}_g$. The calculated $\text{Fe}{L}_{2,3}$ near-edge x-ray absorption spectrum agrees reasonably with experiment, whereas the presence of an unquenched orbital moment is corroborated by a recent discovery in $\alpha \text{-FePc}$ of a very large hyperfine field of positive sign [Filoti et al., Phys. Rev. B 74, 134420 (2006)]. It is suggested that the orbital moment of FePc should be observed more directly in x-ray magnetic circular dichroism experiments.

• Received 30 September 2008

DOI:https://doi.org/10.1103/PhysRevB.79.024413