Using the stochastic Langevin model, we calculate the evolution of postsaddle giant dipole resonance (GDR) $\gamma$-ray multiplicity ($M_{\gamma }$) as a function of the postsaddle friction strength ($\beta$) with excitation energy for ${}^{240}$Cf, ${}^{224}$Th, and ${}^{200}$Pb systems. It is found that with raising the excitation energy the sensitivity of the postsaddle $\gamma$ emission to friction is substantially increased. We further find that $M_{\gamma }$ shows a greater sensitivity to $\beta$ with increasing size of the fissioning nucleus. The results suggest that on the experimental side, populating those fissioning systems with a large size and a high energy favors better determination of the postsaddle friction strength by measuring the GDR $\gamma$ multiplicity emitted in the fission process.

• Received 2 July 2013

DOI:https://doi.org/10.1103/PhysRevC.88.054606