On Temperature Determination from Rotational Raman Line Intensities

Abstract

A theoretical investigation of temperature determination from the pure rotational Raman spectra of diatomic and linear molecules is performed. Calculations are presented on the suitable selection of the lines used to minimize the random error. The problem is formulated in terms of rotational characteristic temperatures. Our results show, for single-channel detection, that temperature determination from the intensity ratio of only two properly selected lines is superior to the evaluation of many lines. Optimum line pairs are calculated for the most widely used molecules, H2 and N2, in the temperature range 300 to 2000 K. The random errors to be expected in this temperature range are given in a form which allows estimates to be made for any particular experimental situation.