We report on exclusive measurements of angular momentum gated high energy gamma rays from hot rotating ¹⁸⁸Os nucleus at two different beam energies. The spectra were measured at four different angles w.r.t. the beam direction for both beam energies. Statistical model fits to the spectra and the analysis of the anisotropy pattern for the high energy data (E_beam=84 MeV, corresponding to an effective compound nuclear temperature T_eff \sim 1.8 MeV) seem to indicate a non-collective oblate shape for the compound nucleus. The shape at the lower beam energy (65 MeV) could not be determined unambiguously. The data for the higher beam energy is in qualitative agreement with our finite temperature potential energy surface (FTPES) calculations. We have observed significant enhancement in the high energy tail of the spectrum in the region of the IVGQR even after a very meticulous subtraction of the cosmic ray background. Further analysis is on to explain the excess counts in this region.

PACS numbers: 24.30.Cz, 24.60.Dr, 24.60.--k, 27.70.+q