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Abstract

After a general introduction into the field of molecular magnets the
discussion focuses on a more specific description of their most
important representative species, single-molecule magnets incorporating
transition metal ions. We overview traditional model approaches for the
phenomenological description of such systems and outline some ways used
to parameterize the corresponding models from experiment and from
first-principle calculations. The latter can be either
multi-determinantal quantum chemical schemes or those based on the
density functional theory. In particular we discuss Heisenberg exchange
parameters and magnetic anisotropy constants. As a practical example,
an introduction into problems and proper-ties of some single-molecule
magnets which gained much attention within last years, namely
Mn-12-acetate, "Fe-8" and "V-15" systems, is given. This introduction
into systems is followed by a critical comparison of calculation
schemes based on the density functional theory that are particularly
well suited for the study of molecular magnets. For the above systems
we select some benchmark results, obtained by different methods.
Finally, we outline our recent progress in the study of other
single-molecule magnets, including six-membered "ferric wheels",
"ferric stars" and "Ni-4" molecules, which we studied with the use of
first-principles methods SIESTA and NRLMOL. (c) 2006 WILEY-VCH Verlag
GmbH & Co. KGaA, Weinheim.