Buffer gas effect on monitoring I2 by a laser induced fluorescence method

Based on the measured N₂ pressure dependence of high resolution fluorescence excitation spectra for ¹²⁷I₂ near the He-Ne laser frequency, effects of the N₂ pressure on the I₂ detection limit and isotopic selectivity of an on-line I₂ monitor using a laser induced fluorescence method are discussed. A possible influence from NO₂, which is contained in reprocessing off-gas streams, on monitoring I₂ is also examined. The ¹²⁷I₂ in N₂ at atmospheric pressure is detected down to a concentration of 5 × 10¹² molecules cm⁻³ by a ³He-²⁰Ne laser induced fluorescence method.