Gibbs Free Energy, Enthalpy, Entropy, and Specific Heat in Constant Pressure of Diatomic Substances Using Improved Tietz-Hua Potential

Abstract

We have theoretically studied the thermodynamic properties of diatomic molecules such as O₂ (X³ \(\Sigma _{g}^{ + }\)), NO (X² \({{\Pi }_{r}}\)), and N₂ (X¹ \(\Sigma _{g}^{ + }\)) using improved Tietz-Hua potential with statistical mechanics framework. To this end, we have solved the Schrödinger equation with the diatomic molecules interaction model via supersymmetric approach within the non-relativistic quantum mechanics background and have obtained energy eigenvalues of the system. Applying the obtained energy spectrum, we have determined partition function using the Poisson summation formula and have deduced thermodynamic properties of the considered molecules such as Gibbs free energy, enthalpy, entropy and specific heat in constant pressure. We have compared our results with (1) experimental data and (2) Tietz-Hua potential model and have determined absolute average deviations. The comparisons reveal that our results have a good agreement with experimental data. Also, our results show that the improved Tietz-Hua potential has a better results rather than Tietz-Hua potential.