Single-particle and collective excitations in the transitional nucleus Os-166


Stolze S., Grahn T., Julin R., Joss D. T. , Andgren K., Auranen K., ...More

JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS, vol.48, no.12, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 48 Issue: 12
  • Publication Date: 2021
  • Doi Number: 10.1088/1361-6471/ac2889
  • Title of Journal : JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS
  • Keywords: mean lifetimes, RDDS measurements, gamma-ray spectroscopy, collectivity, single-particle states, electromagnetic transitions, DATA SHEETS, SHAPE COEXISTENCE, PLUNGER, STATES, GE

Abstract

The mean lifetimes of the lowest energy 2(+), 8(+) and 9(-) states in Os-166 have been measured using the recoil distance Doppler-shift method in conjunction with a selective recoil-decay tagging technique. These measurements extend studies into the most neutron-deficient mass region accessible to current experimental methods. The B(E2; 2(+) -> 0(+)) = 7(2) W.u. extracted from these measurements is markedly lower than those observed in the heavier even-mass Os isotopes. The 8(+) and 9(-) states yield reduced transition probabilities that are consistent with single-particle transitions. While these values may indicate a departure from collective structure, the level scheme and the underlying nuclear configurations can also be interpreted in terms of a simple collective picture. This contrasting behaviour suggests an intriguing dichotomy in the description of heavy transitional nuclei.