DOUBLE EXCHANGE IN TETRAMERIC TETRAHEDRAL CLUSTERS WITH 2-ELECTRON TRANSFER - MAGNETIC-PROPERTIES

A theoretical model is worked out to study the magnetic properties of mixed-valence tetrameric tetrahedral clusters d(n)-d(n)-d(n+1)-d(n+1) (n = 0-4) with two-electron transfer. To calculate the energy levels o f systems a computational procedure based on the second quantization t echnique and group theory approach is used. The exchange-tunnel states of d(n)-d(n)-d(n+1)-d(n+1) (n = 0-4) tetrahedral tetrameric clusters with two-electron transfer are considered. The nature of the ground sp in state of above mentioned systems is determined. The structures unde r consideration are shown to have the magnetic properties which differ in principle from the clusters with a single migrating electron (or h ole).