Signature splitting of electromagnetic transitions in ⁷⁵Kr

The levels in ⁷⁵Kr have been identified via the reaction ⁴⁶Ti(³²S, 2pn)⁷⁵Kr. Excitation functions were measured at beam energies of 85-150 MeV. From n- gamma gamma and gamma gamma coincident measurements at beam energy of 90 MeV, two bands of ⁷⁵Kr have been established. Spins and parities have been assigned to the levels from angular distribution measurements and excitation functions. A positive parity band built on the ground state assigned 5/2⁺ from systematics was observed to 13/2⁺ and a negative parity band to 11/2^-. These bands are interpreted as built on the well-deformed prolate Nilsson orbitals (422)5/2⁺, or equivalently g₉2/(m=5/2), and (301)3/2^-, respectively. The spin sequence in both bands is I=K, K+1, K+2. . ., characteristic of strong-coupled Nilsson states, but the energies and electromagnetic properties exhibit systematic deviations from strong-coupled rotational behaviour. These deviations can be semiquantitatively understood in terms of rotational signature splitting for a prolate, slightly triaxial shape ( beta approximately=0.37, gamma <or approximately=15 degrees ).