Microscopic Derivation of Collective Hamiltonian by Means of the Adiabatic Self-Consistent Collective Coordinate Method Shape Mixing in Low-Lying States of 68Se and 72Kr

The microscopic dynamics of oblate-prolate shape coexistence/mixing phenomena in 68Se and 72Kr are studied by means of the adiabatic self-consistent collective coordinate (ASCC) method in conjunction with the pairing-plus-quadrupole (P+Q) Hamiltonian, including the quadrupole pairing interaction. A quantum collective Hamiltonian is constructed, and exci-tation spectra, spectroscopic quadrupole moments and quadrupole transition properties are evaluated. The effect of the time-odd pair field on the collective mass (inertia function) of the large-amplitude vibration and the rotational moments of inertia about three principal axes is evaluated. It is found that the basic properties of the shape coexistence/mixing are qualitatively reproduced. The results of the calculation indicate that the oblate-prolate shape mixing decreases as the angular momentum increases. Obtaining a microscopic understanding of nuclear collective dynamics is one of the goals of nuclear structure theory. The quasiparticle random phase approx-imation (QRPA), based on the Hartree-Fock-Bogoliubov (HFB) mean field, is a well-known theoretical approach to the collective dynamics, but it is applicable onl