The effect of Jahn-Teller coupling in hexacyanometalates on the magnetic anisotropy in Cyanide-Bridged Single-Molecule magnets

Abstract

The factors that govern the nature of the lowest spin-states and the magnetic anisotropy in mono- and oligonuclear cyanide complexes of 3d-metal ions are analyzed on the basis of a combination of density functional theory (DFT) and ligand field theory (LFT), the ligand field density functional theory approach (LFDFT). In this chapter we analyze first the factors that govern the magnetic anisotropy in the low-spin [Fe(CN)6]3-(2T2g) complexes - the Jahn-Teller activity (vibronic coupling) within the triply degenerate ground states as well as unquenched orbital momenta which influence the spin subsystem via spin-orbit coupling. In a second step we derive the parameters of the spin-Hamiltonian in a general form of a binuclear {(L)CuII-NC-FeIII(CN)5} unit and discuss on this basis the factors that govern its magnetic anisotropy. The nature of the lowest spin multiplet and the spin anisotropy gap are analyzed for this system using first principles.