The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 26 1 2026 05 22 Thermodynamic analysis of 89Y and 166Er nuclei using the nuclear level density parameter within the framework of the GBCS and Ignatiuk models Thermodynamic analysis of 89Y and 166Er nuclei using the nuclear level density parameter within the framework of the GBCS and Ignatiuk models 25 34 3786 10.47176/ijpr.26.1.62128 FA Khosrow Benam Department of Physics, Faculty of Basic Sciences, Shahrekord University, Shahrekord, Iran 0000-0002-4867-6398 Journal Article 2025 06 23 <span>In this research, the thermodynamic properties of the nucleus have been investigated using the temperature-dependent level density parameter. Calculations have been carried out based on the BSC and Ignatyuk models. A well-known limitation of the BCS model is that the gap parameter drops to zero at the critical temperature, which leads to discontinuities and the appearance of singular points in the heat capacity curve. To overcome this problem, the gap parameter in the BCS model has been replaced with an order parameter derived from the generalized Ginzburg-Landau theory, and the resulting improved model was introduced as GBCS. Subsequently, the temperature-dependent level density parameter has been calculated using the GBCS and Ignatiuk models. Finally, by utilizing the temperature-dependent level density parameter, the thermodynamic quantities of the nucleus such as the nuclear level density, entropy, and heat capacity have been obtained using the mentioned models and compared with available experimental data.</span> <span>In this research, the thermodynamic properties of the nucleus have been investigated using the temperature-dependent level density parameter. Calculations have been carried out based on the BSC and Ignatyuk models. A well-known limitation of the BCS model is that the gap parameter drops to zero at the critical temperature, which leads to discontinuities and the appearance of singular points in the heat capacity curve. To overcome this problem, the gap parameter in the BCS model has been replaced with an order parameter derived from the generalized Ginzburg-Landau theory, and the resulting improved model was introduced as GBCS. Subsequently, the temperature-dependent level density parameter has been calculated using the GBCS and Ignatiuk models. Finally, by utilizing the temperature-dependent level density parameter, the thermodynamic quantities of the nucleus such as the nuclear level density, entropy, and heat capacity have been obtained using the mentioned models and compared with available experimental data.</span> https://ijpr.iut.ac.ir/article_3786_34306d99c63613fad5b2a140398c0420.pdf