VIBRATIONAL-STATES ON THE ISOMERS IN DEFORMED-NUCLEI

The mathematical formalism of description within the quasiparticle-pho non nuclear model of vibrational states on two-, three-and four-quasip article isomers is presented. The vibrational states on the, K-pi = 16 (+) isomer in Hf-178, on the K-pi = 25/2(-)-isomer in Hf-179 and on th e K-pi = 9 isomer in Ta-180 are calculated, It is shown that there are many fast gamma-ray transitions from the isomers to the energy range of 5-6 MeV in Hf-178 and to the energy ranges of 2.6-3.0 and 3.4-3.6 M eV in Ta-180. The energy of the neutron capture states on the isomer H f-178(m2) is 6 MeV above the yrast line, It is shown that there are fa st gamma-ray cascades from the K-pi = 31/2 and 33/2(+) components of c apture states to the isomer (HF)-H-179 with K-pi = 25/2(-). This is a unique case to study the fragmentation of five-quasiparticle states mu ch above the yrast line. Investigation of the fragmentation of many-qu asiparticle and many-quasiparticle X phonon states is necessary to stu dy the order-to-chaos transition in nuclei. (C) 1998 Elsevier Science B.V.