Population of triaxial rotor levels in 182Os.

Abstract

A $K$-isomeric state in $^{182}\mathrm{Os}$ with spin $I=(20\ifmmode\pm\else\textpm\fi{}2)\ensuremath{\hbar}$ and half-life equal to 100 ns is found to decay in flagrant violation of the usual $K$-selection rules. The observations---still preliminary---are on the other hand readily understood if it is assumed that the yrast configuration of $^{182}\mathrm{Os}$ becomes triaxial above the backbend, and that the decay proceeds via the numerous collective levels of the triaxial rotor.