αdecay of Po and Rn isotopes using different choices of impinging frequency

Abstract

A comprehensive study of $\ensuremath{\alpha}$ particle emergence from $^{188\text{--}218}\mathrm{Po}$ isotopes is carried out within the framework of the preformed cluster model (PCM). The mass asymmetry coordinate and the interfragment separation play crucial roles in the identification of the most probable decay channel and the barrier penetration of decay fragments. First, the barrier characteristics are studied using two choices of radii [with surface diffuseness (${C}_{i}$) and without surface diffuseness (${R}_{i}$)]. The fragmentation behavior of $^{188}\mathrm{Po}$, $^{202}\mathrm{Po}$, and $^{218}\mathrm{Po}$ isotopes is explored for the identification of the most probable decay channel in view of the structure of the fragmentation potential. The $\ensuremath{\alpha}$ decay is found to be the most prominent decay mode in the chosen set of isotopes. The preformation and penetrative probability of the decay fragments is studied with respect to increase in the neutron number of the parent nucleus. The $\ensuremath{\alpha}$ decay half-lives of polonium isotopes are calculated using classical assault frequency (${\ensuremath{\nu}}_{c}$) and quantum mechanical assault frequency (${\ensuremath{\nu}}_{q}$) and a comparison is made with the experimental data. Here, the term assault frequency is basically the impinging frequency of an $\ensuremath{\alpha}$ particle near the surface of the parent nucleus. Further, the $\ensuremath{\alpha}$ decay half-lives of the $^{198\text{--}220}\mathrm{Rn}$ isotopes are calculated using the effective assault frequency (${\ensuremath{\nu}}_{e}$) parameter, and a comparison is made with the available experimental data.