Pairing and the structure of the pf-shell N∼Z nuclei

The influence of the isoscalar and isovector L = 0 pairing components of the effective nucleon-nucleon interaction is evaluated for several isobaric chains, in the framework of full pf shell model calculations. We show that the combined effect of both isospin channels of the pairing force is responsible for the appearance of T = 1 ground states in N = Z odd-odd nuclei. However, no evidence is found relating them to the Wigner energy. We study the dependence of their contributions to the total energy on the rotational frequency in the deformed nucleus Cr-48. Both decrease with increasing angular momentum and go to zero at the band termination. Below the backbending their net effect is a reduction of the moment of inertia, more than half of which comes from the proton-neutron channel. (C) 1998 Published by Elsevier Science B.V. All rights reserved.