The application ofCW laser collisionally induced fluorescence modellingto determine neon excited-state electron collisional rate coefficients

Abstract

We describe a method for the determination of rate coefficients forcollisional excitation out of the 1s states of a noble gas usingcontinuous-wave laser collisionally induced fluorescence(CW LCIF, i.e. fluorescencefrom an upper level which is not that of the laser transition).The intensity of CW LCIF lines from an upper 2p level that isstrongly coupled to an influential 1s level is dominated bythe electron collisional rate out of that level. By anappropriate choice of LCIF line we fit our recently publishedtheory to experimental observations to determine a set ofelectron collisional direct 1s mixing and 1s-2p excitationrate coefficients. The values of coefficients determined inthis way show very good agreement with those which have beencalculated using cross section data from the literature withthe measured electron temperature. For cases where accuratecross section data are available for the 1s-2p transitionsCW LCIF diagnostics should, via these rate coefficients, provide reliablevalues of the bulk electron temperature.