Photoemissive and recombination reactions of atomic chlorine

Abstract

The red glow emitted from partially dissociated chlorine has been shown to occur via the termolecular reaction, k 1 4 c1+ c1* + Clz+ c1; + Cl., followed by the emission process, From measurement of the absolute quantum yield of emission, and quenching of the emission by Cl2, k14 = 0.94 x 1015 cm6 mole-2 sec-1, and the radiative lifetime of Clt = l/kls> 3 x 10-7 sec. Addition of argon to the chlorine gave the reaction rate forkl8 c1+ C1* -t-Ar+ Cl; + Ar as klg = 2.35 x 1014 cm4 mole-2 sec-1. concentrations ; the process occurs via the two consecutive reactions : Rates of recombination of chlorine atoms were investigated using the red emission to measure atom k9 k-9 c1+ c 1 2 + c 1 3 kltl C13+C1---tCl~+C1~. k 9 = 9.09 x lo7 cm3 mole-1 sec-1, k-9< 7.6 x lo5 sec-1, and under experimental conditions [C13] > 1 . 2 ~ 10-5 [Cl]. Recombination of chlorine atoms with argon as third body has given the overall termolecular rate constant for the reaction, k23 C1+ C1+ Ar-+ C12+Ar as 4-25 f0.8 x 101s cm6 mole-2 sec-1.

Direct observation and reactions of Cl3 radical

“…We used the chemical kinetic simulator software and the rate constants listed in Table IV. Hutton and Wright suggested the upper limit value of k ͑2͒ to be 2.8ϫ 10 −10 cm 3 molecule −1 s −1 at 298 K. 3 Although the experimental data have large error bars, it is safe to say that k ͑2͒ is estimated to be in the order of the collisional cross section or ͑2.5-4͒ ϫ 10 −10 cm 3 molecule −1 s −1 .…”

“…Fluorine containing trihalogens were observed and characterized in rare gas matrices using infrared ͑IR͒ absorption and Raman spectroscopy. [9][10][11][12][13] Hutton and Wright 3 proposed a formation mechanism of trichloride radical Cl 3 from Cl atom recombination in the presence of Cl 2 , Cl + Cl 2 + M → Cl 3 + M , ͑1a͒…”

“…[1][2][3][4] Crossbeam scattering experiments by Lee and co-workers [5][6][7][8] suggested the existence of bound trihalogens in the gas phase reactions. Fluorine containing trihalogens were observed and characterized in rare gas matrices using infrared ͑IR͒ absorption and Raman spectroscopy.…”

“…Time-resolved cavity ring-down spectroscopy [26][27][28][29] ͑CRDS͒ was used to search for the electronic transition of Cl 3 . We obtained theoretically the equilibrium constants for reactions ͑1a͒ and ͑1b͒ and experimentally the rate constants for reactions ͑1a͒, ͑1b͒, and ͑2͒.…”

Tropospheric photooxidation of CF&lt;sub&gt;3&lt;/sub&gt;CH&lt;sub&gt;2&lt;/sub&gt;CHO and CF&lt;sub&gt;3&lt;/sub&gt;(CH&lt;sub&gt;2&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;CHO initiated by Cl atoms and OH radicals

“…In the absence of fluoroaldehyde, only Reactions (R7) and (R8) are taking place, where k prec is the bimolecular rate coefficient for that reaction and k diff is the first-order diffusion rate coefficient of the oxidant out of the detection zone. The reaction of Cl atoms with its photochemical precursor, Cl 2 , is negligible (Hutton and Wright, 1965), but the reaction of OH radicals with H 2 O 2 is a significant contribution to the decay of OH concentration (Sander et al, 2006, Jiménez et al, 2004. So, under these conditions, the oxidant concentration profile should follow a simple exponential rate law:…”