Author/Authors :
A. Harder، نويسنده , , F. D?nau، نويسنده , , K.P. Lieb، نويسنده , , R.A. Cunningham، نويسنده , , W. Gelletly، نويسنده , , C.J. Gross، نويسنده , , F. Hannachi، نويسنده , , M.K. Kabadiyski، نويسنده , , H.A. Roth، نويسنده , , D. Rudolph، نويسنده , , J. Simpson، نويسنده , , ?. Skeppstedt، نويسنده , , BJ.Varley، نويسنده , , D.D. Warner، نويسنده ,
Abstract :
A detailed study of the positive parity yrast and yrare rotational bands in 77Rb is presented. Using the reaction 40Ca(40Ca, 3p) and the EUROGAM I spectrometer, γγγ coincidences enabled us to follow both bands over a large spin range and to measure many E2 strengths. The moments of inertia and transition quadrupole moments indicate that a more deformed band (ϵ2 ≈ 0.38) is crossed by a less deformed one (ϵ2 ≈ 0.29). Since the yrare band starts at the extremely low spin value of I = 92, the conventional band crossing mechanism of two aligning high-j quasiparticles is excluded. The frequency-dependent equilibrium shapes were calculated with Nilsson-Strutinsky type calculations using a diabatic tracing of configurations near the neutron Fermi level. This is the first observation of such a band crossing.
