Experimental and theoretical studies on the electronic properties of vanadium-benzene sandwich cluster anions, V_nBz_n+1 ^- (n = 1-5)

Vanadium-benzene cluster anions, V_nBz_{n +1}^- (Bz = C₆H₆) were generated by laser ablation and supersonic jet methods, and studied using photoelectron spectroscopy. The density functional theory was employed to compute their geometric and electronic structures. It is concluded that the V _nBz_n+1^- anions exhibit multiple-decker sandwich structures similar to their corresponding neutrals, and the adiabatic electron affinity increases with the cluster size. Our computation shows that the excess electron of the anion occupies the d orbitals of the vanadium atoms and that it is delocalized one-dimensionally. Furthermore, a very large HOMO-LUMO gap difference between majority and minority spin orbitals is observed for both the neutrals and the anions, and the V _nBz_n+1^0/- clusters are found to be completely spin-polarized. These facts confirm the possibility of using V _nBz_n+1 clusters as spin filters.