Investigation of the type of quadrupole pairing force in superdeformed nuclei

The variations of moments of inertia of superdeformed (SD) bands Hg-194(1) and Hg-192(1) With angular momentum (rotational frequency) are investigated using the particle-number conserving (PNC) method for treating the cranked shell model. Calculations show that if both the monopole and Y-20 quadrupo le pairing forces are taken into account, the observed omega variation of t he moments of inertia of Hg-194(1) and Hg-192(1) can be reproduced very wel l both in the low-omega and high-omega ranges, in particular the J((2)) dow nturn of Hg-194(1) and the flattening in J((2)) of Hg-192(1) at (h) over ba r omega greater than or equal to0. 40MeV. On the contrast, the calculated J ((2)),s with the Y2+/-1 or Y2+/-2 quadrupole pairing forces are in disagree ment with the experiments. The microscopic mechanism of the omega variation of J((2)) is clearly exhibited in the PNC calculation (the contributions t o J((2)) from various major shells and individual cranked Nilsson orbitals, the occupancy of each cranked Nilsson orbital etc). The omega variation of moment of inertia is the result of the competition among the shell effect (single particle motion in a deformed potential), pairing correlation, Paul i blocking effect and Coriolis (anti-pairing) interaction.