E2/M1 Mixing Ratios Between Low-Lying States in Deformed Even-Even Nuclei

In order to study electromagnetic transitions between low-lying states in deformed even-evennuclei in the SU(3) limit of the framework of IBM-2, we consider the proton-neutron quadrupoleinteraction in the SU(3) Hamiltonian as a perturbed term which breaks F-spin symmetry. Wecalculate the matrix elements of SU(3) generators by using the 1/N expansion method whoseformalism is similar to that of the standard collective model. M1 transition rates and E2/M1mixing ratios between low-lying states in deformed nuclei are given in closed form. The final resultsfor the E2/M1 mixing ratios are applied to 154Gd and 168Er, which have the typical spectra ofaxially-symmetric rotation, and are compared with the experimental data.