Density Functional Calculations of Magnetic Exchange Interactions in Polynuclear Transition Metal Complexes

Abstract

Two effective computational approaches for the study of magnetic exchange interactions in large molecules are\ndiscussed and tested on a number of model systems, namely, broken-symmetry (BS) and single-determinant (SD)\nmodels. Both methods are based on the density functional theory (DFT) but exploit different approximations to\ndeal with multiconfigurational problems. Our results show that the BS model provides semiquantitative results\nfor widely different situations, such as metal-radical interactions and metal-metal interactions mediated by inert\norganic bridges. Although more refined (and expensive) methods are needed for truely quantitative work, the\nBS/DFT approach provides a very useful tool for the rationalization of magneto-structural correlations and for\nthe comparison of different bonding situations in large systems involving transition metal atoms.