Angular momentum transfer in incomplete fusion

Isomeric cross section ratios of evaporation residues formed in 12C + 93Nb and 16O + 89Y reactions were measured by recoil catcher technique followed by off-line γ-ray spectrometry in the beam energy range of 47.4-77.5 MeV for 12C and 57.6-93.3 MeV for 16O. The isomeric cross section ratios were resolved into that for complete and incomplete fusion reactions. The angular momentum of the intermediate nucleus formed in incomplete fusion was deduced from the isomeric cross section ratio by considering the statistical de-excitation of the incompletely fused composite nucleus. The data show that incomplete fusion is associated with angular momenta slightly smaller than critical angular momentum for complete fusion, indicating the deeper interpenetration of projectile and target nuclei than that in peripheral collisions. (author)