Study of parity-doublet structure in the 147La nucleus

Abstract

The work reports several new excited states in the neutron-rich 147La nucleus, populated in spontaneous fission of 252Cf. The excitation scheme has been reinvestigated by means of γ-ray spectroscopy, using high-fold γ coincidences measured with the Gammasphere array of Ge detectors. It is shown that the 229.65-keV level has spin and parity 11/2-, which changes the 9/2- spin-parity reported in a recent evaluation and sets up the spinparity of the ground state as 5/2+. New levels allow to arrange the excitation scheme of 147La into a parity-doublet-like structure showing that the 147La nucleus may have an octupole deformation.