Abstract
<jats:p>Accurate determination of intermolecular potential parameters is essential for predicting thermophysical properties of real gases, particularly heavy polyatomic fluorides of industrial relevance. In this study, Morse potential parameters for MoF6, IF5, and WF6 gases were obtained using a nonlinear least-squares fitting algo rithm based on Lennard–Jones (12–6) interaction energy data, where the root-mean-square error (RMSE) was used as the minimization criterion. The obtained parameters were validated by calculating the second virial coefficient, heat capacity at constant pressure, and speed of sound, and comparing the results with available experimental data over the temperature range 298–400 K. Quantitative accuracy was assessed using RMSE, mean relative error (MRE), and correlation coefficient (R). For the second virial coefficient, RMSE values were 31, 264, and 149 cm3·mol–1 for MoF6, IF5, and WF6, respectively, with corresponding MRE values of 3.3 %, 11 %, and 18.5 %, and strong correlations (R ≥ 0.978). In addition, deviations for speed of sound and heat capacity remained within 1–2 % and below 1 %, respectively, with R > 0.996. These results demonstrate that the proposed approach provides a reliable and computationally efficient framework for modeling inter molecular interactions and predicting thermophysical properties of such gases.</jats:p>