Computational Models for Analyzing the Thermodynamic Properties of Linear Triatomic Molecules

This study presents analytical models for simulating the thermal properties of linear triatomic systems, using the modified Rosen–Morse oscillator and harmonic oscillator potential to represent vibrational modes. The models employ existing partition functions to derive the thermodynamic functions for the symmetric, asymmetric, and 2-fold degenerate bending modes. These thermodynamic functions are applied to gaseous triatomic molecules such as BO2, HCN, N3, and Si2N. The results demonstrate high accuracy, with mean percentage absolute deviations (MPAD) of less than 0.17% for molar entropy and Gibbs free energy. For enthalpy and heat capacity, MPAD values are below 2% compared to National Institute of Standards and Technology (NIST) data. The findings are in strong agreement with the existing literature on gaseous triatomic molecules, confirming the reliability of the proposed models.