©Author(s) 2022. Tis article is published with open access at https://jnp.chitkara.edu.in. ISSN No.: 2321-8649(Print) ISSN No.: 2321-9289(Online); Registration No. : CHAENG/2013/51628 J. Nucl. Phys. Mat. Sci. Rad. A. Vol. 9, No. 2 (2022), pp.131–136 Journal of Nuclear Physics, Material Sciences, Radiation and Applications Journal homepage: https://jnp.chitkara.edu.in/ Theoretical Investigation of α-decay Chains of Fm-Isotopes Joshua T. Majekodunmi 1, N. Jain 2, Shilpa Rana 2*, K. Anwar 1, N. Abdullah 1 M. Bhuyan 3, and Raj Kumar 2 1 Institute of Engineering Mathematics, Faculty of Applied and Human Sciences, Universiti Malaysia Perlis, Arau, 02600, Perlis, Malaysia 2 School of Physics and Materials Science, Thapar Institute of Engineering and Technology, Patiala, Punjab 147004, India 3 Center for Theoretical and Computational Physics, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia * srana60_phd19@thapar.edu (Corresponding Author) ARTICLE INFORMATION ABSTRACT Received: December 25, 2021 Accepted: May 9, 2022 Published Online: June 20, 2022 Background: The theoretical and experimental investigations of decay properties of heavy and superheavy nuclei are crucial to explore the nuclear structure and reaction dynamics. Purpose: The aim of this study is to probe the α-decay properties of 243 Fm and 245 Fm isotopic chains using the relativistic mean-feld (RMF) approach within the framework of the preformed cluster-decay model (PCM). Methods: The RMF densities are folded with the relativistic R3Y NN potential to deduce the nuclear interaction potential between the α particle and daughter nucleus. The penetration probability is calculated within the WKB approximation. Results: The α-decay half-lives of even-odd 243 Fm and 245 Fm isotopes and their daughter nuclei are obtained from the preformed cluster-decay model. These theoretically calculated half-lives are found to be in good agreement with the recent experimental measurements. Conclusions: The novel result here is the applicability of the scaling factor within the PCM as a signature for shell/sub-shell closures in α-decay studies. We have also demonstrated that N=137, 139 and Z=94 corresponding to 231,233 Pu could be shell/sub-shell closures. The least T 1/2 is found at 243,245 Fm which indicate their individual stability and α-decay as their most probable decay mode. Keywords: α-decay, Relativistic mean-feld, Preformed cluster-decay model, Preformation, Half-lives DOI: 10.15415/jnp.2022.92020 1. Introduction Alpha decay is the most prominent mode of decay in the heavy and superheavy nuclei (SHN). Gamow [1], Gurney and Condon [2] independently provided the frst theoretical explanation of the alpha decay process through the Quantum tunneling phenomenon. Since then, myriad of experimental as well as theoretical eforts have been devoted to probe the alpha decay properties of various nuclei [3-9]. Te study of alpha decay provides insightful information about the nuclear structure, shell closure and fusion-fssion dynamics [3-9]. Te detection of alpha decay chains from an unknown nucleus followed by spontaneous fssion provides an efcient tool to identify the synthesis of new elements in superheavy region [6-9]. Moreover, the exploration of alpha decay properties of actinides also plays an important role in materials science [10]. Numerous theoretical models such as the generalized liquid drop model (GLDM), multi-channel cluster model (MCCM) and density dependent cluster model (DDCM) etc. have been developed to probe the α-cluster radioactivity [11-14]. Generally, the alpha particle is perceived to pre- exist within the parent nucleus before its emission [15-17]. Te quantum mechanical fragmentation theory (QMFT) based preformed cluster-decay model (PCM) also reinforces the theory of α-preformation [18-20]. In the PCM, an α-cluster is supposed to be preborn inside the parent nucleus which afterwards penetrates the interaction barrier formed due to the interplay between the attractive nuclear potential and repulsive Coulomb potential [18-20]. Te deduction of Coulomb potential formed between the daughter nuclei and α-particle is straightforward unlike the nuclear potential. Various phenomenological, semi-microscopic and microscopic models have been adopted for the estimation of nuclear potential [20] and references therein. Te double folding approach [21] equipped with relativistic mean-feld (RMF) densities and microscopic R3Y nucleon-nucleon (NN) potential have also been