The spectrum shape and the angular distribution of γ rays from highly excited and rotating ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$ compound nuclei were measured and analyzed. The results are in good agreement with theory including both intrinsic-shape fluctuations and shape-orientation fluctuations about an equilibrium shape which changes from spherical to oblate deformed with increasing spin.

• Received 30 July 1990

DOI:https://doi.org/10.1103/PhysRevLett.65.2523