title: Magnetostructural correlations in polynuclear complexes: the Fe4 butterflies.
abstract: Theoretical methods based on density functional theory have been employed to analyze the exchange interactions in Fe4 butterfly complexes. Three exchange coupling constants, calculated using a hybrid functional, provide an accurate description of the experimental magnetic susceptibility. The largest coupling constant corresponds to the interaction between the central and external iron atoms and presents a strong dependence on the Fe-O bond distance and the Fe-O-Fe angle of the central Fe2O2 core. An excellent linear correlation is found between such exchange coupling constants and a function of the spin population of the iron atoms, that is related with the square of the overlap of the "magnetic orbitals", according to the Kahn-Briat model.
authors.affiliation: Departament de Química Inorgànica and Centre de Recerca en Química Teorica, Universitat de Barcelona, Diagonal 647, 08028 Spain.
authors.forename: Thomas
authors.initials: T
authors.lastname: Cauchy
authors.forename: Eliseo
authors.initials: E
authors.lastname: Ruiz
authors.forename: Santiago
authors.initials: S
authors.lastname: Alvarez