We have used angle-dependent soft x-ray absorption spectroscopy to stu
dy the nature and orientation of the unoccupied states of V2O5, V6O13,
VO2, and V2O3. In the oxygen K edge (vanadium L(III) and L(II)) spect
rum of V6O13 and V2O5, pre edge features are apparent; these vary dram
atically with the angle between crystal axes and the polarization vect
or of the incident synchrotron radiation. The O K- edge (V L- edge) x-
ray absorption spectra probe unoccupied states of O 2p (V 3d) symmetry
, and the angular dependence thus reveals the spatial orientation and
character of these hybridized O 2p - V 3d molecular orbitals in those
highly anisotropic materials.