Neutron capture studies of 189Os

An extensive study of the level structure of 189Os has been carried out using the (n, γ) and (n, e−) reactions. The use of the average resonance capture technique ensures that the complete set of 12−, 32− states has been established up to 1500 keV in excitation energy and secondary γ-rays have been measured in singles and coincidence to build up the detailed level scheme. The results are compared with existing Nilsson model calculations and with the results of algebraic models. None of the approaches are able to provide a satisfactory description of the negative-parity states.