Systematic study for the mass distribution of fission fragments in the neutron rich region
ABSTRACT The systematic data on the fission fragment mass distribution for nuclei ranging from Z = 88 to 120 relevant to the r-process nucleosynthesis is constructed in a semi-empirical way. The mass distribution is estimated from the potential energy surface by means of the liquid drop model with the shell energy correction and also by referring the results in the dynamical calculation of fission paths by the Langevin equation in the three-dimensional deformation space. The results are compared with the mass asymmetric values at the saddle point driven by the extended Thomas-Fermi Struchinsky integral (ETFSI) model. In the lighter nuclei Z < 100, our results are consistent with the values of ETFSI, on the other hand in the heavier nuclei our estimation gives a larger mass asymmetry and approaches to zero due to the decrease of shell effect beyond Z > 120.