Rotational structure of T = 0 and T = 1 bands in the N = Z nucleus 62Ga

The rotational behavior of T = 0 and T = 1 bands in the odd-odd N = Z nucleus Ga-62 is studied theoretically using the spherical shell model (laboratory frame) and the cranked Nilsson-Strutinsky model (intrinsic frame). Both models give a good description of available experimental data. The role of isoscalar and isovector pairing in the T = 0 and T = 1 bands as functions of angular momentum is studied in the shell model. The observed backbending in the T = 0 band is interpreted as an unpaired band-crossing between two configurations with different deformation. The two configurations differ by 2p-2h and are found to terminate the rotational properties at I-pi = 9(+) and I-pi = 17(+),respectively. E2-decay matrix elements and spectroscopic quadrupole moments are calculated. From the CNS calculation, supported by shell model results, it is suggested that the low spin parts of the bands with T = 0 and T = 1 correspond to triaxially deformed states with the rotation taking place around the shortest axis (positive gamma) and intermediate axis (negative gamma), respectively. At lower spins the configuration space Pf(5)/(2)g(9)/(2), used in the shell model calculation, is found sufficient while also f(7/2) becomes important above the backbending. (C) 2001 Elsevier Science B.V. All rights reserved.