Abstract

CO₂ laser irradiation of SF₆/hydrocarbon mixtures are shown to produce positive ions and infrared fluorescence due to emission by HF^≠. The mechanism for the production of these ions and fluorescence involves the multiple photon dissociation of SF₆ and subsequent attack of the free fluorine atom on the hydrocarbon, as well as V → V transfer and thermal ionization reactions. Argon and oxygen are found to increase ion production while quenching the fluorescence. Chemi-ionization of the hydrocarbons by a reaction sequence initiated by the attack of fluorine atoms on trace amounts of an oxygen impurity cannot be disregarded as a channel for ion formation.