EFG calculations for Cu 2 + compounds

The electric field gradients at Cu in various binary and ternary Cu2+ oxides and halides, including several antiferromagnetic parent compounds of high-Tc superconductors, have been calculated with the full-potential linearized augmented plane wave method. The data from NOR are very well reproduced with the inclusion of Coulomb-correlation corrections (U). Not even an approximate agreement is obtained without U. Also many other properties of the 14 solids investigated are well accounted for.