Exploring various features of the reaction mechanism involved in the collision of Li7 on Cu

Abstract

Nuclear reaction induced by a weakly bound projectile on light-medium mass targets poses open questions on the fusion mechanism. It is seen that fusion suppression in such reactions is negligible, but that stands on the basis of scarcely available experimental data. Thus more experimental data are demanded to bring out a clear understanding. In the course of this, for the first time, a measurement of residual cross sections from $^{7}\mathrm{Li}$ induced reaction on $^{\mathrm{nat}}\mathrm{Cu}$ has been presented in this article within the 2.3--6.0 MeV/nucleon energy range. The residues $^{69,67,66}\mathrm{Ge}$, $^{68,67,66,65}\mathrm{Ga}$, and $^{69m,65,63}\mathrm{Zn}$ produced in the reaction have been identified by $\ensuremath{\gamma}$-ray spectroscopy. The measured excitation function of the residues has been analyzed using equilibrium and preequilibrium reaction models in the framework of empire-3.2.2 to understand the reaction mechanisms involved in the low energy region. The underlying reaction mechanism is shown to be a blend of equilibrium and preequilibrium processes. The intensity of the $\ensuremath{\gamma}$ peak 93.31 keV arising in the decay of $^{67}\mathrm{Ga}$ has been revised experimentally. The experimental intensity turns out to be about half the value reported in different nuclear databases. Fusion cross sections have been estimated using the experimental data and empire-3.2.2 code. The estimated fusion cross sections are in line with coupled channel calculations taking inelastic excitations into account. The large production cross section of medically important $^{67}\mathrm{Ga}$ has been measured.