Calculation of the mean probability of photon capture for vacuum UV line emission of fluorine in the case of a thermal plasma mixture

•The mean probability of photon capture (Ψul) is calculated for fluorine emission.•The resonance lines of fluorine are strongly subjected to self-absorption.•The Doppler and collision broadening mechanisms are considered.•(Ψul) is suitable for self-absorption quantification in vacuum UV spectral region.•Ψj for recombination continuum is also investigated.

The mean probability of photon capture for the resonance lines emitted by a neutral fluorine atom is calculated assuming a Voigt line shape. The calculations allow a quantitative estimate of the self-absorption effect of spectral lines of neutral fluorine atoms occurring far below the ultraviolet (UV) spectral range. The calculations are made for the bound–bound resonance lines emitted at 95.48, 77.81, 95.85, 79.44 and 77.94 nm in the case of SF6-N2 thermal plasma mixture. The dependence of the mean probability of photon capture on the Doppler and collision (Stark, resonance and van der Waals) broadening mechanisms is considered. The same method is equally applied to free–bound transitions of the recombination continuum. The variation of the mean probability of photon capture with the temperature, the SF6 proportions and the size of the plasma are considered. The results obtained may be of practical importance in plasma modeling and plasma diagnostics. In view of its simplicity, the method may also be applied to laser-induced breakdown spectroscopy (LIBS) spectral analysis.