LOW-ENERGY DIPOLE GAMMA-RAY TRANSITION RATES IN EVEN-EVEN DEFORMED-NUCLEI

A study of low-lying magnetic and electric dipole excitations is carri ed out in Er-166,Er-168, Yb-172,Yb-174, and Hf-178 within the quasipar ticle-phonon nuclear model with the wave functions consisting of one- and two-phonon terms. It is shown that computed M1 strength below 4 Me V in these nuclei is much stronger fragmented than in Gd and Dy isotop es in agreement with the relevant experimental observation. The scisso rs state is strongly fragmented and the overlapping between the scisso rs state and any 1(+) state is less than 0.1. The fragmentation of the one-phonon 1(+) states, as a rule, is stronger than the fragmentation of the one-phonon states with K-pi = O- and 1(-). The resulting M1 an d E1 spectra are compared with available experimental data. The calcul ated M1 and E1 strengths summed in the energy range 2-4 MeV are in agr eement with the relevant experimental data.