Role of hexadecupole deformation in the shape evolution of neutron-rich Nd isotopes

Abstract

A new isomer with ms half-life was observed in 160Nd at RIBF, RIKEN Nishina Center by using in-flight fission of a 238U beam and a cluster-type Ge detector array EURICA. The experimental results and a PSM calculation indicate that the isomer in 160Nd is a 2 quasi-particle excitation of neutrons with a configuration of v1/2[521] × v7/2[633] as the case in other N = 100 isotones. The E(4+)/E(2+) ratio of the ground-state band, 3.29, shows the 160Nd is well deformed and the ground band has a rotational nature. The 4- excitation of Nd showed an increase in energy by ∼100 keV compared to that of 162Sm as predicted by the PSM calculation. A PSM calculation was performed by changing input β4 value and confirmed that the large hexadecupole deformation in Nd was responsible for the increase of the isomer energy.