Reaction mechanism coexistence in the 123 MeV 19F+56Fe reaction.

Abstract

Mass and charge identified ejectiles, spanning from $^{11}\mathrm{B}$ to $^{22}\mathrm{Ne}$, have been detected in the 123 MeV $^{19}\mathrm{F}$${+}^{56}$Fe reaction. The coexistence of deep inelastic collision (DIC) and incomplete fusion (IF) mechanisms has been observed. The shape of the energy spectra and their behavior with angle allowed us to identify two components: The less dissipative one was dominating near the grazing angle. For both components experimental optimum Q values were derived. Two approaches based on the sum rule (SR) model of Wilczy\ifmmode \acute{n}\else \'{n}\fi{}ski were used to calculate DIC and IF contributions to the complex fragment cross sections. Both prescriptions fit reasonably well experimental ejectile cross sections and Q optimum values. Results of the present investigation support the idea that the DIC can be treated on the same footing as IF in the SR model once the first process is confined in an inner angular momentum window, starting from the maximum fusion angular momentum, with respect to quasielastic processes. \textcopyright{} 1996 The American Physical Society.