Reflection symmetry of the near-yrast excitations in 145Ba

Excited states in Ba-145, populated in spontaneous fission of Cm-248, have been studied by means of gamma spectroscopy, using high-fold gamma coincidences measured with the EUROGAM2 array of Ge detectors. The 507.7-keV level, which has been assigned in this work spin and parity 9/2(+), belongs to the i(13/2) intruder band. We have identified in Ba-145 a new 9/2(2)(-) level at 346.3 keV and a band on top of it. The negative parity indicates that it is not due to an octupole excitation. The position of the 5/2(-) ground state, relative to the positive-parity band, could be reproduced by calculations with a reflection-symmetric potential and we do not observe a parity doublet to the ground state. Therefore we conclude that octupole excitations in Ba-145 are most likely due to octupole vibrations coupled either to the reflection-symmetric ground state or to the i(13/2), decoupled neutron configuration.