A method for predicting the entropy and Gibbs free energy of ICl and BrCl gases based on an improved Hulburt-Hirschfelder potential

Abstract

Combined with the Rydberg-Klein-Rees (RKR) data and spectral constants, a method based an improved Hulburt-Hirschfelder (IHH) potential model for calculating the molar entropy and Gibbs free energy of diatomic gases is presented. The full set of rovibrational energy is calculated by solving the one-dimension Schrödinger equation using the determined IHH potential pointwise data, and then the partition function, Gibbs free energy and entropy of the diatomic molecular gas can be determined using the quantum statistical ensemble theory. Comparing with other potentials and thermodynamic data, the application to the ground electronic state of ICl and BrCl gases shows that the IHH potential fits well with the experimental RKR data, and the calculated Gibbs free energy and molar entropy are in good agreement with the experimental values.