Simulation of the fission dynamics of the excited compound nuclei ²⁰⁶Po and ¹⁶⁸Yb produced in the reactions ¹²C + ¹⁹⁴Pt and ¹⁸O + ¹⁵⁰Sm

A two-dimensional dynamical model based on the Langevin equation was used to study the fission dynamics of the compound nuclei ²⁰⁶Po and ¹⁶⁸Yb produced in the reactions ¹²C + ¹⁹⁴Pt and ¹⁸O + ¹⁵⁰Sm, respectively. The fission cross section and average pre-scission neutron multiplicity were calculated for the compound nuclei ²⁰⁶Po and ¹⁶⁸Yb, and results of the calculations compared with the experimental data. The elongation coordinate was used as the first dimension and the projection of the total spin of the compound nucleus onto the symmetry axis, K, considered as the second dimension in the Langevin dynamical calculations. In the two-dimensional calculations, a constant dissipation coefficient of K and a non-constant dissipation coefficient have been used to reproduce the abovementioned experimental data. It is shown that the two-dimensional Langevin equation can satisfactorily reproduce the fission cross section and average pre-scission neutron multiplicity for the compound nuclei ²⁰⁶Po and ¹⁶⁸Yb by using constant values of the dissipation coefficient of K equal to γ_κ = 0.18(MeV zs)^-1/2 and γ_κ = 0.20(MeV zs)^-1/2 for the compound nuclei ²⁰⁶Po and ¹⁶⁸Yb, respectively. (authors)