Partition functions for diatomic molecules in plasmas out of thermal equilibrium

Two calculation methods on the partition functions for diatomic molecules in plasmas out of thermal equilibrium are reported. A Boltzmann distribution for the electronic, vibrational and rotational quantum levels are assumed in the two calculation methods. The results obtained by two methods are displayed for four sorts of diatomic molecules, O₂, N₂, OH and NO, that are present in humid air plasmas. The calculation of density for the electronically excited states is developed. Finally, a method to calculate the partition functions to simulate the non-normalised diatomic spectra is discussed.