Microscopic analysis of shape mixing in low-lying states of proton-rich nuclei in the Se-Kr region

Abstract

Using the five-dimensional quadrupole collective Hamiltonian, we study the oblate-prolate shape coexistence/mixing phenomena in the low-lying states of proton-rich nuclei in the A=70-90 region from a viewpoint of oblate-prolate symmetry and its breaking. To derive the collective Hamiltonian microscopically, we have developed a new method, on the basis of the adiabatic self-consistent collective coordinate method, for determining the collective potential, the vibrational and rotational inertial masses in it. By solving the collective Schrödinger equation, we calculate excitation spectra, spectroscopic quadrupole moments and electric quadrupole transition probabilities among the low-lying states. The result of the calculation clearly indicates the dominant role of the large-amplitude vibration in the triaxial shape degree of freedom. It also exhibits an interesting effect of rotation, which may be called 'rotational hindrance to the oblate-prolate shape mixing', that is, the growth of localization of the collective wave function in the (β, γ) deformation space assisted by the rotational motion.