Global modelling of the observed line positions: Dunham coefficients for the ground state of 16OH molecule

A global treatment of the available experimental data on infrared and microwave transitions of 33 vibration-rotation bands for the ground state and the data on the electronic system B2Σ+-X2Π of 16OH molecule was carried out. In this analysis, a global model with vibrational dependences of the parameters of the effective Hamiltonian for the diatomic molecule in the 2Π electronic state was used. As a result of the fit, a set of the ‘Dunham-type’ coefficients was obtained. They reproduce the experimental dataset of the rovibrational and pure rotational transitions as well as the data on the electronic system B2Σ+ - X2Π, within estimated experimental uncertainties. The determined ‘Dunham-type’ coefficients were compared with those known previously.