$^{\text{7}}$Li-induced reaction on $^{\text{nat}}$Mo: A study of complete versus incomplete fusion

TL;DR

This study investigates the fusion dynamics of $^{7}$Li on natural molybdenum, highlighting the dominance of incomplete fusion processes over complete fusion at energies slightly above the Coulomb barrier, supported by experimental and theoretical analysis.

Contribution

It provides experimental cross section data for evaporation residues and compares them with theoretical models, demonstrating the significant role of incomplete fusion in $^{7}$Li-induced reactions.

Findings

Significant cross section enhancement in $ ext{α}$-emitting channels.

Incomplete fusion fraction increases with projectile energy.

Theoretical models confirm ICF's contribution over CF.

Abstract

Several investigations on the complete-incomplete fusion (CF-ICF) dynamics of $\alpha$-cluster well-bound nuclei has been contemplated above the Coulomb barrier ($\sim$ 4-7 MeV/nucleon) in recent years. It is therefore expected to observe significant ICF over CF in the reactions induced by a weakly bound $\alpha$-cluster nucleus at slightly above the barrier. In order to investigate CF-ICF in the loosely bound system, $^{\text{7}}$Li beam was bombarded on the $^{\text{nat}}$Mo foils, separated by the aluminium (Al) catcher foils alternatively, within $\sim$ 3-6.5 MeV/nucleon. Evaporation residues produced in each foil were identified by the $\gamma$-ray spectrometry. Measured cross section data of the residues were compared with the theoretical model calculations based on the equilibrium (EQ) and preequilibrium (PEQ) reaction mechanisms. The experimental cross section of $^{\text{101m,100,99m,97}}$Rh, $^{\text{97,95}}$Ru, $^{\text{99m,96,95,94,93m+g}}$Tc and $^{\text{93m}}$Mo residues measured at various projectile energies were satisfactorily reproduced by the simplified coupled channel approach in comparison to single barrier penetration model calculation. Significant cross section enhancement in the $\alpha$-emitting channels was observed compared to EQ and PEQ model calculations throughout observed energy region. The ICF process over CF was analyzed by comparing with EMPIRE. The increment of the incomplete fusion fraction was observed with increasing projectile energies. Theoretical model calculations reveal that compound reaction mechanism is the major contributor to the production of residues. Theoretical evaluations substantiate the contribution of ICF over the CF in $\alpha$-emitting channels.