Magnetism and multiplets for Fe-phthalocyanine molecules were investigated based on the constraint density functional theory (DFT) by imposing a density matrix constraint on the d-orbital occupation numbers. We demonstrate that for a single FePc molecule, there are three stationary states of multiplets, 3 E g, 3 A 2g, and 3 B 2g, and that the magnetic anisotropy (MA) strongly depends on the multiplet structures. The ground state of the 3 A 2g obtained from the constraint DFT total energy calculations has planar MA, with the spin moments pointing along the molecule's planar direction. The columnar stacking structure for α-FePc, with the ground state of the 3 E g, shows planar MA.
- First-principles calculations
- Magnetic anisotropy
- Molecular magnets
ASJC Scopus subject areas
- Physics and Astronomy(all)