Nuclear fission with diffusive dynamics

We investigate the dynamics of nuclear fission, assuming purely diffusive motion up to the saddle point. The resulting Smoluchowski equation is solved for conditions appropriate to the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ${+}^{142}$Nd${\to }^{158}$Er reaction at 207 MeV. The solution is characterized by an equilibration time ${\mathrm{\tau }}_0$ for the system to reach steady state, and the fission decay rate in steady state, Λ. We find that the equilibration time ${\mathrm{\tau }}_0$ plays a very small role in determining the number of prescission neutrons. The diffusion coefficient extracted from the experimental data is larger than the theoretical in the work of Bush, Bertsch, and Brown by a factor of 5–11.