Quenching of I(²P_1/2) by NO₂, N₂O₄, and N₂O

Abstract

Quenching of excited iodine atoms (I(5p5, 2P1/2)) by nitrogen oxides are processes of relevance to discharge-driven oxygen iodine lasers. Rate constants at ambient and elevated temperatures (293-380 K) for quenching of I(2P1/2) atoms by NO2, N2O4, and N2O have been measured using time-resolved I(2P1/2) --> I(2P3/2) 1315 nm emission. The excited atoms were generated by pulsed laser photodissociation of CF3I at 248 nm. The rate constants for I(2P1/2) quenching by NO2 and N2O were found to be independent of temperature over the range examined with average values of (2.9 +/- 0.3) x 10(-15) and (1.4 +/- 0.1) x 10(-15) cm3 s(-1), respectively. The rate constant for quenching of I(2P1/2) by N2O4 was found to be (3.5 +/- 0.5) x 10(-13) cm3 s(-1) at ambient temperature.

O2(a1Δ) quenching in the O/O2/O3 system

“…The photolysis radiation was provided by an excimer laser (Lambda Physik Compex Pro 102, 10 ns pulse duration) operating at 248 nm (KrF). The photolysis cell has been described in recent publications [16][17][18][19]. It was constructed from a solid brass block with 1 cm diameter channels for the flow of gases, the passage of the photolysis laser beam, and the observation of emission from the photolysis zone.…”

Recent advances in the development of discharge‐pumped oxygen‐iodine lasers

“…This effect has been partly attributed to the removal of O atoms by the sequence (12) (13) Oxygen atoms in the discharge lead to the undesirable formation of O , and this chemistry is also suppressed by the addition of NO. Fortunately the presence of NO and NO in the lasing medium is acceptable as both are inefficient quenchers of I* and O (a) [30].…”

“…To date the reactions (27) and (28) www.lpr-journal.org have been examined. The F or Cl atoms were derived from the reactions (29) and (30) The use of DI is preferred for reaction (27) as HF is a much more aggressive quencher of I* than DF. Chemical generation of I atoms by both schemes has been demonstrated.…”