Abstract
The spins and parities of low-lying states in 72 Br populated in the beta decay of 72 Kr have been 14 studied via conversion electron spectroscopy. The measurements were carried out at ISOLDE using 15 a mini-orange spectrometer with Si(Li) and HPGe detectors for electrons and γ-rays detection. 16 Results of the conversion coefficients corresponding to transitions de-exciting 12 levels in 72 Br are 17 reported. The multipolarities of the transitions are deduced and the spins and parities of the levels 18 involved are discussed. From the multipolarities of the most intense transitions to the ground state, 19 the spin and parity of the 72 Br ground state have been definitely established as 1 +. The spin of 20 the 101.2-keV isomeric state is determined to be 3 −. The level scheme is compared with mean-field 21 and shell-model calculations and oblate deformation for the 72 Br ground state is deduced. No E0 22 transitions have been found in 72 Br. E0 transitions in the neighbouring isobaric nuclei, 72 Se and 23 72 Ge, have also been studied. 24