The kinetics of monochromatization of plasma light emission

This paper is concerned with the monochromatization of the visible spectrum of rare gas discharges upon addition of either oxygen, hydrogen or chlorine gas: the M-effect. This phenomenon, observed over 20 years ago at the National Institute for Lasers, Plasma and Radiation Physics (Bucharest), is clearly explained here for the first time. The explanations contain references to all most relevant previous work on this subject. Assuming that the exacerbation of a given emission line results from the collisional interaction between an electropositive gas (the rare gas) and an appropriate electronegative gas, a general method, based on calculation of the energy balance of their excited energy levels, is developed for determining the gas mixtures for which the M-effect can be obtained, along with the corresponding wavelength of the monochromatic emission. These calculations show that the M-effect is highly probable in discharges combining inert gases with oxygen or hydrogen. The experimental results are in perfect agreement with these calculations. The M-effect is an important fundamental effect in physics and has much potential for applications requiring monochromatic light sources for both research and industry.