UC Irvine

O17 nuclear-magnetic-resonance spectra are obtained, using uniaxially aligned powder of YBa2Cu3O7, and resonance lines from the four inequivalent oxygen sites are clearly distinguished. Principal components of the electric field gradient (EFG) and the shift tensors are obtained in the normal state. Assigning the direction of the largest EFG components of Cu-O bond axes, the anisotropy of the shift suggests that the spin density at the plane O(2,3) and the bridging O(4) sites resides on the pσ orbitals. The domonant contribution to the spin susceptibility comes from Cu d states.