Effects of Deformation-dependent Shell Correction on Isotope Effect of Emission of Prescission Neutron near Neutron 126 Closure-shell

The effect of deformation-dependent shell correction (DDSC) on the emission of prescission neutron (EPN) is studied within a dynamical and statistical model for three isotopes of ^209,213,217Fr near the neutron 126 closure-shell. The results show that the fission barriers are enhanced with DDSC, and the increment of ²¹³Fr is almost 2 times those of ^209,217Fr, but those saddle points are not changed. Although the enhancement of fission barrier delays nuclear fission, the fission dynamics process is controlled by the competition between thermodynamic driving force (TDF) and nuclear damping, so the deformation-dependence of nuclear dissipation must be considered in order to extract the role of shell correction. The shell correction doesn't alter isotope effect of EPN with OBD nuclear dissipation in the first phase of nuclear fission, but the rule does not been exhibited because that there is abnormal enhancement of TDF using SPS nuclear dissipation. The increment of EPN caused by the rise of fission barrier is countered by the competition between TDF and nuclear damping in the second phase of nuclear fission, hence the effect of EPN cannot exhibit. The effect of DDSC on EPN near the neutron 126 closure-shell is dominated by the rules in the first phase of nuclear fission.