Vibrational and single-particle states in ²³⁵U

The level structure of ²³⁵U has been studied by secondary γ-rays and their conversion coefficients, following thermal neutron capture in ²³⁴U. A level scheme containing 39 levels was established; 12 levels have been assigned to the following configurations, resulting from the coupling of quasi-particle states to vibrational excitations of the core: {left open angle bracket}[631↓]+0⁺{right open angle bracket}, {left open angle bracket}[631↓]-2⁺{right open angle bracket}, {left open angle bracket}[631↓]+0^-{right open angle bracket}, {left open angle bracket}[622↑]+0⁺{right open angle bracket}, {left open angle bracket}[622↑]-2⁺{right open angle bracket}. The excitation energy of the 1 2⁺ isomeric state was found to be 74±4 eV, which is of considerable interest in the understanding of the electronic structure of UO₂.