Significant role of deformation in probing postsaddle nuclear dissipation with light particle emission

Using a one-dimensional Langevin model, we study the effects of deformation on the multiplicities of postsaddle neutrons, protons, α particles, and giant dipole resonance (GDR) γ rays of a heavy fissioning system 240Cf as probes of postsaddle nuclear dissipation (β). It is shown that postsaddle dissipation effects on these light particles have a significant deformation dependence. Furthermore, we find that the role of deformation depends on the type of the particle. It reduces the sensitive influence of β on protons, α particles, and GDR γ rays substantially, whereas it enhances the sensitivity of neutrons to β. The results suggest that to accurately extract the postsaddle friction strength by comparing measured prescission particle multiplicities of heavy nuclei with calculations based on statistical models or stochastic equations like Langevin equations, it is important to take into account the deformation effects. The influence of model dimensionality is discussed.