A M VINODKUMAR

Department of Physics, University of Calicut, Calicut 673 635, India

E-mail: attukalathil@gmail.com

Abstract. The capture-fission cross-section is measured for the

collision of the massive nucleus $^{132}$Sn with $^{96}$Zr at

near-barrier energies and compared with the collision of $^{124}$Sn

with $^{96}$Zr. This study gives insight into fusion enhancement and

hindrance in systems involving neutron-rich nuclei.

The dinuclear system model (DNS) calculations

describe the excitation function reasonably well and if we use the

barrier heights predicted by this model we can conclude that fusion

hindrance (represented by extra push energy) is greater for the more

neutron-rich systems.

The fusion excitation function for $^{9}$Li + $^{70}$Zn  and

$^{9}$Li + $^{208}$Pb systems are measured for near-barrier energies

using ISAC1 and ISAC2 Facilities at TRIUMF. The $\alpha$-emitting

evaporation residues ($^{211-214}$At) are stopped in the $^{208}$Pb

target and their decay is measured.  The measured excitation

function shows evidence for large enhancements in the sub-barrier

energies, which is not accounted by current theoretical models.

Suppression of the above-barrier cross-section with respect to these

theoretical models are also seen.