Polarization Corrections for Shielding and Antishielding Configurations of the Copper Atom

The level-crossing technique has been used to measure the hyperfine structure constants of the ${\mathrm{Cu}}^{63}$ nucleus in the ${\mathrm{}\left(3d\right)\mathrm{}}^{10}4p {}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ state. To extract a value for the nuclear quadrupole moment, configuration interaction effects are allowed for by performing a least-squares fit to the energy levels. The value obtained is in serious disagreement with a value for $Q$ inferred from the ${\mathrm{}\left(3d\right)\mathrm{}}^9{\mathrm{}\left(4s\right)\mathrm{}}^2$ configuration. The copper moment may therefore serve as a test for Sternheimer or other polarization corrections that must be invoked to explain the discrepancy.