ELECTRIC-FIELD GRADIENTS AT CD-111 IN BINARY OXIDES

The electric field gradients (EFGs) of Cd-111 at substitutional sites in binary oxides of different crystal structures obtained in perturbed angular correlation (PAC) experiments are collected and compared to point charge model (PCM) calculations. The error of the calculated EFGs is estimated from the experimental error in the crystal parameters. The PCM seems to be a good approximation for oxides with bond lengths exceeding d congruent-to 2.1 angstrom and here the theoretical shielding factor gamma(infinity) can be used. The application of radially dependent shielding factors for d less-than-or-equal-to 2.1 angstrom where covalent bonding prevails is discussed.