Systematic study of microscopic nuclear level densities of Sn isotopes within a relativistic framework*

Abstract Nuclear level density (NLD) plays a crucial role in describing the statistical properties of excited nuclei and is a key input for models of compound nuclear reactions, such as those used in nuclear astrophysics and reactor physics. In this study, we construct microscopic nuclear level densities for Sn isotopes by combining single-particle spectra, pairing correlations, and deformation parameters derived from relativistic Hartree–Bogoliubov (RHB) calculations with the combinatorial method. We examine the energy dependence and isotopic systematics of the calculated level densities. In particular, we analyze their variation with excitation energy and neutron number, and compare them to available experimental data, including cumulative low-lying levels and s -wave neutron resonance spacings ( ). The resulting level densities are further employed as input to Hauser–Feshbach calculations of radiative neutron capture cross-sections [Nuclear Data Sheets 120 , 272 (2014)]. Our results demonstrate that RHB-based nuclear level densities provide a reliable microscopic framework for describing Sn isotopic level densities and accurately predicting cross-sections.