Nuclear structure of Yb-172

Detailed angular distributions of the Yb-173(d,t)Yb-172 and Yb-171(t,d)Yb-1 72 reactions have been measured, using 15 MeV beams of deuterons and triton s, and reaction products were analysed with a magnetic spectrograph. The an gular distribution for each peak was compared with DWBA predictions to extr act spectroscopic strengths for components of different e-values. These str engths were compared with values calculated from the microscopic compositio ns of states predicted by the Quasiparticle-Phonon Nuclear Model (QPNM), Fo r this purpose, new QPNM calculations using an extended set of base states were performed and are reported. Techniques were developed for performing C oriolis mixing calculations on single-phonon states (i.e., superpositions o f two-quasiparticle components). For the first time a good understanding ha s been obtained for the microscopic structures of the K-pi = 2(+) band at 1 608 keV and K-pi = 3(+) band at 1663 keV, which are strongly mixed. Sixteen rotational bands up to 2.6 MeV are interpreted, in addition to many states above 2 MeV which have strong (t,d) populations associated with severely f ragmented configurations. The QPNM is very successful in providing a detail ed description of the large set of strengths measured. An exception is that for some K-pi = 0(+) bands above the first excited one at 1043 keV, more s trength is predicted than observed. (C) 1999 Elsevier Science B.V. All righ ts reserved.