超交換相互作用について

抄録

The super-exchange interaction in certain magnetic compounds is treated on the basis of an approach which takes into account the spatial correlation between the electrons of the intervening ions.
This is achieved by formulating the appropriate semilocalized or alternant orbitals for these electrons, The conditions which lead to ferromagnetic and anti-ferromagnetic spin coupling between magnetic ions are explores for three centre and four electron system. It is found that if the lowest excited orbital of the system has an appropriate symmetry then the lowest state is a singlet in which electrons of the magnetic ions have anti-parallel spins.
Quantitative estimates for the three centre and four electron system in MnO gives reasonable agreement with the observed Néel temperature. Spin operator formalism is also given.