Half-life of the yrast 2+ state in 188W: Evolution of deformation and collectivity in neutron-rich tungsten isotopes

Abstract

The half-life of the yrast Iπ=2+ state in the neutron-rich nucleus 188W has been measured using fast-timing techniques with the HPGe and LaBr3:Ce array at the National Institute of Physics and Nuclear Engineering, Bucharest. The resulting value of t1/2=0.87(12) ns is equivalent to a reduced transition probability of B(E2;21+→01+)=85(12) W.u. for this transition. The B(E2;21+→01+) is compared to neighboring tungsten isotopes and nuclei in the Hf, Os, and Pt isotopic chains. Woods-Saxon potential energy surface (PES) calculations have been performed for nuclei in the tungsten isotopic chain and predict prolate deformed minima with rapidly increasing γ softness for 184-192W and an oblate minimum for 194W. © 2013 American Physical Society.