Proton states in 191Ir and 193Ir populated by the (3He, d) and (α, t) reactions

The proton states in 191Ir and 193Ir have been studied using (3He, d) and (α, t) reactions. The beams of 28 MeV 3He and 4He particles were obtained from the University of Rochester model MP tandem Van de Graaff accelerator and the reaction products were analysed with an Enge split-pole magnetic spectrograph. Transfer l-values were obtained from cross-section ratios of the two stripping reactions and spectroscopic factors were extracted using DWBA calculations. The present results reveal that the extreme single-particle shell model does not predict the observed level structure in the iridium region, whereas the Nilsson model appears to be fairly successful. It has been shown that Coriolis mixing must be included in the model, with matrix elements of half strength providing good agreement with experiment. The 32+[402], 112−[505], 52+[402], 12−[541] and 12−[530] Nilsson orbitals are identified in both iridium isotopes. The K0−2 and K0+2 γ-vibrations based upon the ground state appear to be mixed with the 12+[400] and 72+ [404] orbitals, respectively. The 12+ [660] orbital may have been located, but with appreciable fragmentation of its strength.