Local density functional theory applied to spin coupling in Fe6S65+ supercluster

Using density functional theory (DFT), the multiplicity of the ground state was determined for Fe6S6Cl61- ions as well as the order or the excited spi n states. A method to determine the exchange integrals J of the Fe6S65+ clu ster is presented based on these results and a spin-coupling algebra. The f ollowing order of the spin states was established with respect to the total spin 5/2, 1/2, 7/2, 3/2, 9/2, 11/2, 15/2, 13/2, and 17/2. We also calculat ed the Heisenberg coupling parameters J(1), J(2), J(3), and J(4) as 22, 146 , -130, and 81 cm(-1), respectively. The possibility of the ground state of high multiplicity as well as the necessary conditions for such state are d iscussed. (C) 1999 John Wiley & Sons, Inc.