<i>Ab initio</i>calculated XANES and XMCD spectra of Fe(II) phthalocyanine

Abstract

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 $\text{Fe}\text{ }{L}_{2,3}$ 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 $\ensuremath{\alpha}\text{-FePc}$ 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.