Spectroscopic studies of the NCl3 + H reaction sequence as a candidate laser system

In this paper we present results from a spectroscopic and kinetic study of the reaction sequence of NCl 3 + H that produces NCl(a 1 Δ). Using sensitive optical emission diagnostics, we have observed both NCl(a) and (b) produced by this reaction. Upon addition of HI to the flow, the reaction of H + HI produced iodine atoms that were pumped to the excited I( 2 P 1/2 ) state, and we observed strong emission from the I atom 2 P 1/2 → 2 P 3/2 transition at 1.315 μm. We also used a sensitive diode laser spectrometer to probe the I atom transition and observed transfer of population from ground state ( 2 P 3/2 ) to the excited state ( 2 P 1/2 ) with a concomitant reduction in the measured absorption. We interpret this observation as an approach to optical transparency.