Disentangling effects of potential shape in the fission rate of heated nuclei

Abstract

We have compared the results of dynamical modeling of the fission process with predictions of the Kramers formulas. For the case of large dissipation, there are two of them: the integral rate ${R}_{I}$ and its approximation ${R}_{O}$. As the ratio of the fission barrier height ${B}_{f}$ to the temperature $T$ reaches 4, any analytical rate is expected to agree with the dynamical quasistationary rate ${R}_{D}$ within $2%$. The latter has been obtained using numerical modeling with six different potentials. It has been found that the difference between ${R}_{O}$ and ${R}_{D}$ sometimes exceeds $20%$. The features of the potentials used that are responsible for this disagreement are identified and studied. It is demonstrated that it is ${R}_{I}$, not ${R}_{O}$, that meets this expectation regardless of the potential used.