出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：In order to probe the effect of the breakup or transfer induced breakup coupling on the energy
dependence of the optical potential in the presence of conventional quasielastic couplings, the
elastic scattering angular distributions for 67Li on 64Ni have been measured at Tata Institute of
Fundamental Research/Bhabha Atomic Research Centre Pelletron Facility, Mumbai, India. The
experiments were carried out in the energy range of 12 MeV Elab 26 MeV near the Coulomb
barrier (
14 MeV) of respective systems. A phenomenological optical model analysis was performed
for the systems 6Li+64Ni and 7Li+5864Ni, and the behaviours of the surface strengths
of the potential components with decreasing energy were extracted. A further analysis of the
measured angular distributions, along with the existing data for 67Li+58Ni, was performed with
two different model potentials - one with the folded potential normalized with a complex factor
(OMP1) and the other with a hybrid potential composed of a renormalized folded real and a phenomenological
imaginary (OMP2) potential components. All the model potentials predict similar
energy dependent behaviour for the interaction potential around the barrier indicating a model independence
of the observed behaviour. The observed energy dependences of the strengths of the
real and imaginary potentials also corroborate with the dispersion relation prediction for both the
6Li+64Ni and 6Li+58Ni systems. Though the evidence of breakup is distinct in the energy variation
of the potential strengths for 6Li+5864Ni systems, close to the barrier the variation is more
in the line of conventional threshold anomaly. Also the threshold behaviour of the interaction
potential does not indicate any distinct isotopic dependence for 6Li+5864Ni. On the other hand,
though 7Li+64Ni shows normal threshold behaviour, for 7Li+58Ni, the potential does not exhibit
any signicant energy dependence. Unlike 6Li, in case of 7Li a distinct isotopic dependence has
been observed for 58Ni and 64Ni.
