Determination of the rotational temperature and uncertainties

Abstract

Currently there exist many methods how to determine the plasma parameters from molecular spectra. The most widely used method is concerned with the determination of the neutral gas temperature by the pyrometric curves. In case at least one branch in the vibrational band is well distinguished, the Knaus and Caye method is possible to apply. The Janin and Eyraurde method can be used when the vibrational band structure is closed into the simple singlet structure. The statistic and the accuracy of rotational temperature determination must not be omitted. At times this procedure could be difficult since we must know all the measuring method details and be conversant of all the aspects affecting the experimental data. This article describes the methods of rotational temperature determination mentioned above and introduces the analysis sources of uncertainties during the measuring and data processing. The couplings coming from the various sources and their combinations are also presented. The interest of this article lies with their usage in the spectroscopy pointing out that systematic analysis is only one way to correctly interpret the measured data.