− 70 − 60 − 50 − 40 − 30 − 20 − 10 0 0 . 0 0 . 1 0 . 2 0 . 3 0 . 4 0 . 5 0 . 6 single - particle energy [MeV] quadrupole deformation parameter β proton posi t ive nega − 70 − 60 − 50 − 40 − 30 − 20 − 10 0 0 . 0 0 . 1 0 . 2 0 . 3 0 . 4 0 . 5 0 . 6 single-particle energy [MeV] quadrupole deformation parameter β neutro n posi t ive nega FIG. 3: Single-particle energies for protons (upper) and neutrons (lower) are plotted as functions of the quadrupole deformation parameter β of the total system. of the obtained wave functions have approximately parity symmetric shapes, extracted single-particle orbits are almost pure-parity orbits. Figure 3 shows single-particle ener- gies of positive- and negative-parity orbits for protons and neutrons. Two orbits degenerate because of the time reversal symmetry except for β ∼ 0 and 0.3. In the small β region with β < ∼ 0 . 25, the single-particle orbits are normal order for both protons and neutrons, which shows that configurations around the GS minimum are roughly [( sd ) − $^{2}$]$_{π}$ [( pf ) $^{2}$]$_{ν}$ relative to the ground state of $^{40}$Ca. With an increase of deformation β , the highest positive-parity orbits in the sd -shell disappear at β ∼ 0 . 3 and negative-parity orbits come down for both protons and neutrons, which corresponds to the orbit inversion when the pf -orbits intrude into the sd -orbits in the large β region. Consequently, configurations in the large β region with β > ∼ 0 . 35 around the SD minimum are roughly [( sd ) − $^{4}$( pf ) $^{2}$]$_{π}$ [( sd ) − $^{2}$( pf ) $^{4}$]$_{ν}$ . Figure 4 shows the experimental and theoretical excitation energies obtained by the 6