Ab initiotheory of nuclear-quadrupole antishielding effects in metallic systems—application to zinc and cadmium

A first-principles investigation is carried out for the antishielding effects for the field gradients due to conduction electrons in zinc and cadmium. It is found that the field gradient due to conduction electrons external to the core electrons is antishielded in both metals very substantially, by a factor of about 60% of γ_∞ in both cases, while the part of the field gradient due to conduction electrons in the region internal to the core electrons is subject to very little antishielding effect. Our calculated field gradients in the two metals, when combined with the experimental quadrupole coupling constants, lead to quadrupole moments of 0.46 and 0.67 b for ⁶⁷Zn{(9/2)}⁺$ and $¹¹¹Cd(5/2)⁺, the latter agreeing well with a value from ionic crystal data.