Partition function and thermodynamic properties of ZnH, ZnO, and their ions at thermal equilibrium in the temperatures range of 100 K to 20,000 K.

Accurate molecular partition functions are required to determine thermodynamic properties of diatomic molecules. In this study, thermodynamic properties, heat capacity at constant pressure, enthalpy, entropy and Gibbs free energy of ZnO, ZnH, ZnO + and ZnH + are calculated in temperature range of 100 K to 20,000 K. Direct summation over energy levels using recent spectroscopic data and dissociation energy values are used. The influence of the potential choice between Hulburt-Hirschfelder and Morse potentials on the limitation levels in the summation are studied. Estimates are made for the error made between the two approaches with a Hulburt-Hirschfelder potential and a Morse potential on the thermodynamic properties. Finally, heat capacity at constant pressure, enthalpy, entropy and Gibbs free energy and formation enthalpy of ZnO, ZnH, ZnO + and ZnH + are given.