Analytical prediction of enthalpy and Gibbs free energy of gaseous molecules

Abstract

By employing the improved deformed Pöschl-Teller oscillator to describe the internal vibration of a diatomic molecule, new equations for predicting the molar enthalpy and Gibbs free energy of diatomic molecules were obtained. The equations were applied to the ground states phosphorus, nitrogen, and iodine monochloride molecules. Average absolute deviations of 0.8178%, 3.1939%, and 0.5312% from experimental data were obtained using the molar enthalpy equation. The analytical expression of Gibbs free energy yields average deviations of 0.3865%, 0.4360%, and 0.0405% for the diatomic molecules. The results are in good agreement with available literature data on P2, N2, and ICl gaseous molecules.

Keywords

• Partition function
• Entropy
• Enthalpy
• Gibbs free energy
• Gaseous molecules
• NIST data