Double exchange in mixed-valence polynuclear cluster: the contribution of multicentre interaction

Abstract

A method to calculate the tunnelling state energy of mixed-valence clusters using a secondary quantization technique has been developed. This method makes it possible to obtain the analytical form for any matrix elements existing in double-exchange theory and to determine the microstructure of the parameters of this theory. The energy spectrum of trimeric mixed-valence systems d¹-d¹-d² and d⁴-d⁴-d⁵ are calculated, and the magnetic properties of these are investigated.