Toward an effective yet reliable many-body computation of magnetic couplings in bisnitronyl nitroxide biradicals

Configuration interaction calculations have been applied to the study of the magnetic coupling in a series of bisnitronyl nitroxide diradicals. Molecular orbitals obtained with different localization schemes have been considered in the generation of the configuration interaction space, with the aim of investigating the role played by the various fragments in the magnetic interaction. Polyene spacers are found significant, while fragments outside the magnetic-bridge-magnetic moiety can be neglected. (C) 2008 American Institute of Physics.