Spin-orbit coupling of spin-frustrated systems

We have investigated the effects of spin-orbit (SO) interactions on noncollinear molecular magnetism by combining the classical Dzyaloshinsky-Moriya (DM) model and ab initio generalized spin orbital (GSO) method. We have derived an estimation scheme of the magnetic anisotropy energy (MAE) and the Dzyaloshinsky vector based on the SO first-order perturbation theory (SOPT1) for GSO Hartree-Fock (GHF) solutions. We found that the fundamental results of GHF-SOPT1 method can be reproduced by diagonalizing the core Hamiltonian plus SO terms, and that the spin topologies of odd-ring systems can be determined by the topological indices of the singly occupied molecular orbitals. (C) 2004 Wiley Periodicals, Inc. Int J Quantum Chem 102: 80-89,2005.