Temperature determination using molecular spectra simulation

Noisy and spectrally not well resolved molecular emission spectra were employed for evaluation of the rotational and vibration temperature in different plasma sources. This diagnostic method may be applied in a large temperature range. It is especially useful when the apparatus function of a recording system is unknown. The described method is based on a comparison of experimental data with a theoretically calculated spectrum. A numerical minimization procedure is started with the temperature value obtained from the Boltzmann plot or intensity ratio of two selected spectrum components. Examples are given with C-2(d(3) Pi(g),v'=0)-->C-2(a(3) Pi(u),v(")=0) swan band at 516.611 nm, OH(A(2) Sigma(+),v'=0)-->OH(X-2 Pi,v'=0) band at 306.357 nm, and CH(A(2) Delta-X-2 Pi) system around 431.5 nm.