Global modelling of the observed line positions for the spectra of ultraviolet bands: Dunham coefficients for the A2Σ+ excited state of the 16OH molecule

A global treatment of the available experimental data on transition frequencies both in the A2Σ+state and in the A2Σ+−X2Π, and B2Σ+−A2Σ+ electronic systems 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 different electronic state was used. As a result of the fit, a set of the ‘Dunham-type’ coefficients for A2Σ+ electronic state was obtained. They reproduce the experimental dataset within estimated experimental uncertainties. The determined ‘Dunham-type’ coefficients were employed to generate the potential energy curve in the A2Σ+ electronic state using the RKR method.