Evaluation of the rotational temperature in N₂discharges using low-resolution spectroscopy

An improvement of methods for estimating the rotational temperature from the partially resolved 391.44 nm emission band of N 2 + (B 2 u + - X 2 g + ) has been developed by numerically studying this band as a function both of the temperature and of the instrumental function of the detection system. We give a simple tabulation for which one can obtain, without calculation, the rotational temperature in the range 300-900 K from measurements of the band profile considered and the experimental function. The accuracy of the temperature evaluation is better than to within 10%. The approach is validated in the range 340 - 410 K, using measurements of the 391.44 nm band in a pure N 2 dc magnetron discharge.