Determination of interatomic potentials for diatomic molecules from low resolution spectra

Often, experimental spectra with only partially resolved rotational structure are observed. In such cases, determination of potential energy curves for the corresponding electronic states might be not as reliable as in the high resolution studies. In this paper, we estimate the uncertainties of the potential energy curve parameters, obtained from spectra with partially or not resolved rotational structure, where both frequencies and intensities are fitted. As an example, recently reported excitation spectrum of the B31(53P1) <-X10+(51S0) electronic transition in CdAr van der Waals complex is used. Two types of Morse functions are used to model the excited state potential, but method can be readily extended to more complex potential functions. It is shown, that for reliable estimation of the uncertainties of given potential function one should take into account the possible variation of the transition dipole moment function.