DFT studies of the molecular nanomagnet Fe-8 and the V-15 spin system - Electronic structure and magnetic ordering

Based on first-principles all-electron density-functional calculations we r eport the electronic structure and magnetic ordering of the molecular magne t Fe-8 and the V-15 spin system. The ferrimagnetic ordering with total spin S = 10 of the eight iron atoms in the Fe-8 cluster agrees well with experi mental results from polarized neutron data. In comparison the low spin syst em V-15 shows a spin S = 1/2 ground state which is also found from our calc ulations.