Computational Magnetochemistry: Complementary Quantum Mechanical Tools

Magnetic behaviour of condensed magnetic d and f systems with localised ‘magnetic electrons’ is essentially controlled by both single ion effects (interelectronic and spin-orbit coupling, ligand field potential) and interionic exchange interactions. The latter act according to the spin dimensionality forced upon the magnetic centre via the single ion effects. For a complete understanding of magnetic behaviour on the basis of quantum mechanical models a two-step procedure presents itself that determines in a complementary way first the ‘easy’ direction of the centres' magnetic dipoles connected with the single ion ground state. Subsequently, the relevant isotropic/anisotropic spin-spin coupling model is applied (Heisenberg, XY, Ising). With the help of the textbook compounds CrBr3 and Cs3 CoCl5 as well as β-RuCl3 the way of acting is pointed out.