Excitation of octupole, beta- and gamma-vibration band levels of ²³⁸U by inelastic neutron scattering

Experimental data on inelastic neutron scattering are analyzed in a Hauser-Feshbach-Moldauer approach with a coupled-channel estimates of the direct reaction contribution. For the direct excitation of the ground state rotational band levels with J^π = 0⁺, 2⁺, 4⁺, 6⁺, 8⁺ the rigid rotator model was used, whereas for the direct excitation of members of the β-, γ- (K^π = 0₂⁺, 0₃⁺, 2⁺) and first octupole band (K^π = 0^-) a soft-deformable rotator model was used. Quadrupole, octupole, hexadecapole and gamma-deformation parameters are defined by consistent analysis of excited rotational-vibrational band structures and excitation cross sections of the relevant levels. Structures evident in measured neutron emission spectra for E_n ∼ 1-6 MeV are correlated with excitation of levels of K^π = 0^- and K^π = 0₂⁺, 0₃⁺, 2⁺ bands.