Double exchange in tetrameric tetrahedral clusters with two-electron transfer: Magnetic properties

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