The static quadrupole moment $Q_{2^{+}}$ for the 1.982-MeV $2_1^{+}$ state in ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ has been remeasured via Coulomb excitation. Anomalously large $Q_{2^{+}}$ values previously published are shown to be erroneous as a result of Coulomb-nuclear interference and other problems eliminated by the present techniques. Both present and previous data are consistent with $Q_{2^{+}}$ values of - ${3.1}_{-2.0\mathrm{}}^{+3.0\mathrm{}}$ (- ${0.1}_{-2.0\mathrm{}}^{+3.0\mathrm{}}$) $e·{\mathrm{fm}}^2$ for constructive (destructive) interference. This result agrees with shell-model and coexistence-model predictions.

• Received 2 June 1977

DOI:https://doi.org/10.1103/PhysRevLett.39.325