Two-dimensional γ-ray energy correlations have been measured at high spins in ${}_{}{}^{146}{}_{}{}^{}\mathrm{Gd}$ with the anti-Compton spectrometer array OSIRIS. Pronounced ridges have been found consisting of stretched E2 transitions. The separation of the ridges gives a dynamical moment of inertia 2${\mathrm{\theta }}_{\mathrm{band}}^{\mathrm{}\left(2\right)\mathrm{}}$=(150±6)${\mathrm{ħ}}^2$/MeV, suggesting a superdeformation with an axis ratio c/a=1.7 (${\beta }_2$≊0.6). The quadrupole moment of the superdeformed nucleus is $Q_0$${=11\mathrm{}}_{\mathrm{-}4}^{+14\mathrm{}}$ e⋅b. .AE

• Received 9 June 1987

DOI:https://doi.org/10.1103/PhysRevLett.59.2024