The low-lying low-spin levels of ${}_{}{}^{75}{}_{}{}^{}\mathrm{Se}$ have been investigated. These levels were populated via the ${}_{}{}^{75}{}_{}{}^{}\mathrm{As}$(p,nγ${)}^{75}$Se reaction with proton energies between 3.0 and 4.0 MeV. Angular distribution measurements have been used to assign spin values and to determine multipole mixing ratios via compound statistical theory of nuclear reactions. Lifetimes for 17 states in ${}_{}{}^{75}{}_{}{}^{}\mathrm{Se}$ were obtained by the Doppler-shift attenuation method for the first time. For several of the transitions in ${}_{}{}^{75}{}_{}{}^{}\mathrm{Se}$, values or limits for B(M1) and B(E2) were obtained. The negative-parity sequence of levels up to about 2.5 MeV could be predicted well on the basis of the collective model with Coriolis perturbation. An effective moment-of-inertia parameter under the effect of Coriolis perturbation is used to predict these states. The results compare quite well with experimental values.

• Received 17 December 1990

DOI:https://doi.org/10.1103/PhysRevC.44.987