Ab Initio mo Calculations of Superexchange Integrals For Transition-Metal Fluorides: MFM³⁺ (M=Cu(?), Ni(II) and Mn(II)). Active Control of the Magnetic States

Abstract

Ab initio UMP calculations were carried out for binuclear transition- metal fluorides in order to elucidate variations of the superexchange integrals with intermetallic distances. It was shown that the antiferromagnetic superexchange integrals calculated for tricentric systems MFM⁺³ (M=divalent ions) by the approximately spin-projected UMPn (n= 1–4) method with the triple zeta basis set are about −134, −22 and −1 cm⁻¹ in the cases of Cu(?), Ni(II) and Mn(II), respectively. These are consistent with the experimental results available. The hole-or electron doping into antiferromagnetic systems is also discussed in relation to previous proposals to obtain the switching type molecular magnets controlled by thermal, photochemical, electrochemical and other techniques.