On the Theory of the Superexchange Interaction in Ionic Crystals: KNiF3

Abstract Studies are made of superexchange interaction in ionic crystals using the Heitler‐London theory and with particular reference to KNiF 3 . The generalized Heitler‐London quantitative theory of covalency allows a detailed study to be made of the transfer of an electron from cation to cation and the transfer of two electrons from an anion to the cations. No further assumptions are made and the calculations are performed numerically. The antiferromagnetic superexchange constant given by this calculations is in good agreement with the experimental superexchange constant.