Vibration-rotational alternating-parity spectra of even-even nuclei with effective triaxiality

Abstract In the present work, a model combining vibration-rotational motion and effective triaxiality is developed for even–even nuclei with quadrupole and octupole deformations. The Davidson potential is used to solve the radial part of the vibration-rotational Schrödinger equation in the axial quadrupole and octupole variables. In an adiabatic approximation the contribution of the angular variable in the components of the moments of inertia is taken as a constant after which the triaxial-rotor energy is obtained. As a result the alternating-parity spectrum and wave functions of the nucleus with quadrupole-octupole degrees of freedom are obtained. The proposed model is used to describe the yrast and first-non-yrast alternating-parity bands of the even–even nuclei 150 Nd, 154 Sm, 154,160 Gd, 156 Dy, 162,164 Er, 172 Yb, 230,232 Th, 230,232,234,236,238 U and 238,240 Pu. The relevance of the model for taking into account the collective quadrupole-octupole modes in a rather complete form is pointed out.