Transition probabilities and interacting boson-fermion model description of positive parity states in117Sb

Abstract

The Doppler shift attenuation method was used to determine lifetimes in the picosecond region for excited states of ${}^{117}\mathrm{Sb}$ populated with the $(\ensuremath{\alpha},2n\ensuremath{\gamma})$ reaction at ${E}_{\ensuremath{\alpha}}=27.2\mathrm{MeV}.$ Interacting boson-fermion model calculations explain reasonably well the main features of the positive parity levels known up to about 2.5 MeV excitation. The mixing of the lowest one-quasiparticle ${9/2}^{+}$ state with the intruder $(2p\ensuremath{-}1h)$ ${9/2}^{+}$ state, as well as the quadrupole deformation of the intruder band are also discussed.