Temperature fitting of partially resolved rotational spectra

In this paper we present a method to automatically fit the temperature of a rotational spectrum. It is shown that this fitting method yields similar results as the traditional Boltzmann plot, but is applicable in situations where lines of the spectrum overlap. The method is demonstrated on rotational spectra of nitric oxide from an atmospheric pressure microwave plasma jet operated with a flow of helium and air, obtained with two different methods: laser induced fluorescence and optical emission spectroscopy. Axial profiles of the rotational temperatures are presented for the ground NO X state and the excited NO A state.