Cluster decay half-lives using modified generalized liquid drop model (MGLDM) with different pre-formation factors
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ORIGINAL PAPER
Cluster decay half-lives using modified generalized liquid drop model (MGLDM) with different pre-formation factors K P Santhosh*
and T A Jose
School of Pure and Applied Physics, Kannur University, Swami Anandatheertha Campus, Payyanur, Kerala 670327, India Received: 15 July 2019 / Accepted: 19 November 2019
Abstract: Cluster decay from 212–240Pa, 219–245Np, 228–246Pu, 230–249Am, and 232–252Cm has been studied by including three different pre-formation factors that depend on cluster size, atomic number of cluster and daughter nuclei, and Q value in MGLDM, an approach developed by modifying GLDM with proximity 77 potential. In MGLDM, where Q valuedependent pre-formation factor is added, the standard deviation of logarithmic half-lives was found to be 0.83, and the experimental half-lives were successfully reproduced using MGLDM with cluster size-dependent, and atomic number of cluster and daughter nuclei-dependent pre-formation factor with a standard deviation of 0.58 and 0.63, respectively. The half-lives of heavy elements in trans-lead region emitting 22Ne, 24Ne, 26Mg, 28Mg, 32Si and 33Si clusters, which have not been experimentally determined so far, have been predicted by incorporating three types of pre-formation factors to MGLDM. As all the predicted half-lives are below 1030s and are within the experimentally measurable range, we hope that our present predictions would be helpful for future studies in this field. Keywords: Cluster radioactivity; Alpha radioactivity; Half-life PACS Nos.: 23.70.?j; 23.60.?e; 27.90.?b
1. Introduction Cluster radioactivity, the process by which particles heavier than alpha and lighter than fission fragments are emitted, was first predicted by Sandulescu et al. [1] in 1980. The experimental evidence of prediction was confirmed by Rose and Jones [2] in 1984, and in the same year, it was experimentally detected by Aleksandrov et al. [3]. Soon enough, emission of other clusters like 20O, 23F, 22,24,26 Ne, 28,30Mg, and 32,34Si were also detected experimentally [4, 5], and presently, about 20 clusters from 14C to 34 Si have been confirmed to be emitted from parent nuclei ranging from 221Fr to 242Cm [6]. Several theoretical predictions were made to explain the basic concepts behind cluster emission, and eventually the phenomenon of cluster decay was explained in two ways within two models. In the first case, cluster is assumed to be preborn within the parent nuclei before tunneling through the potential barrier, which can be headed as the
*Corresponding author, E-mail: [email protected]
pre-formed cluster model [7–9]. In the second case, parent nucleus is assumed to be deformed continuously as it penetrates the nuclear barrier and the cluster is formed like fission fragments, which is the superasymmetric fission model [10–13]. In unified fission theory [14–17], the decay constant is calculated as the product of assault frequency (mo) and barrier penetrability constant (P), whereas in the pre-formed cluster model [18–21], the pre-formation constant (Pc) is also
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