  The adiabatic self-consistent collective coordinate (ASCC) method is applied
to the pairing-plus-quadrupole (P + Q) model Hamiltonian including the
quadrupole pairing, and the oblate-prolate shape coexistence phenomena in
proton-rich nuclei, 68Se and 72Kr, are investigated. It is shown that the
collective path connecting the oblate and prolate local minima runs along a
triaxial valley in the beta-gamma plane. Quantum collective Hamiltonian is
constructed and low-lying energy spectra and E2 transition probabilities are
calculated for the first time using the ASCC method. Basic properties of the
shape coexistence/mixing are well reproduced. We also clarify the effects of
the time-odd pair field on the collective mass (inertial function) for the
large-amplitude vibration and on the rotational moments of inertia about three
principal axes.
