Observations of gain on the I(~2P_(1/2)→~2P_(3/2)) transition by energy transfer from O_2(a ~1Δ_g) generated by a microwave discharge in a subsonic-flow reactor

摘要

The excitation of I(~2P_(1/2) in the reactions of discharge-generated O_2(a ~1Δ_g) and O(~3P) with I_2 has been investigated in a microwave discharge-flow reactor at 1.5 Torr and ～350 K using a suite of optical absorption and emission diagnostics to detect O_2(a ~1Δ_g), O, I(~2P_(1/2)), and I(~2P_(3/2)) with high sensitivity. For O_2(a ~1Δ_g) yields of 0.20-0.25 generated by the microwave discharge, positive gain on the I(~2P_(1/2)→~2P_(3/2)) transition at 1.315 μm was observed when O concentrations were reduced by reaction with added NO_2. The results imply quenching mechanisms for I(~2P_(1/2) which are much faster than direct collisional deactivation by O.