Ozone flash photolysis

A recent study of the vibrational-to-vibrational (V-V) energy transfer between highly-excited oxygen molecules and ozone combines laser-flash photolysis and chemical activation with detection by time-resolved LIF [ ]. Partial laser-flash photolysis at 532 mn of pure ozone in the Chappuis band produces translationally-... 

Klaning, U. K., K. Sehested, and T. Wolff, Ozone Formation in Laser Flash Photolysis of Oxoacids and Oxoanions of Chlorine... 

Secondary Processes. Snelling et al. (917) followed the consumption of 03 as a function of time after flash photolysis of 03. The results show that the ozone consumption occurs in two distinct stages, a very fast process (less than 50 fisec) followed by a slow process lasting many milliseconds. The fast process is attributed to the reaction... 

Flash photolysis studies of mixtures of ozone and hydrogen (6,56) have shown that the reaction of 0(1D) atoms with hydrogen yields vibra-tionally excited OH radicals. Studies of ozone and hydrogen mixtures in the visible (35) and in the ultraviolet (94) have shown that water is formed and that the rate of ozone decomposition is increased in the presence of hydrogen. 

Mortensen A, Skibsted LH (1998) Reactivity of p-carotene towards peroxyl radicals studied by laser flash and steady-state photolysis. FEBS Lett 426 392-396 Munoz F, von Sonntag C (2000) The reactions of ozone with tertiary amines including thecomplex-ing agents nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) in aqueous solution. J Chem Soc Perkin Trans 2 2029-2033... 

Oxidation rate constant k, for gas-phase second order rate constants, kon for reaction with OH radical, k os with NO3 radical and ko3 with O3 or as indicated, data at other temperatures see reference koe = (2.4 0.7) X 10 cm molecule" S at 298 K was determined using (flash photolysis-resonance fluorescence, Zetzsch Stuhl 1982 quoted, Atkinson 1985, 1989) k(apparent) < 4 x 10 M s for reaction with ozone at pH 8 in water, k < 6.0 x 10 M" S for protonated species, and k < 6.0 x 10" M" S for non-protonated species for the reaction with ozone in water at pH 2-4 and 20-23°C (Hoigne Bader 1983b)... 

McGrath and Morrow " studied the reactions of both 0( D) and 0( P) with cyanogen at room temperature by flash photolysis. The 0( D) was produced by the photolysis of ozone. The reaction was monitored by absorption spectroscopy. At first, they attributed the previously unidentified ultraviolet absorption bands at 3250-3330 A to the fulminate radical (CNO), concluding that the initial step of the reaction was... 

Basco studied the reaction in a similar flash photolysis apparatus, and found the overall rate coefficient for CN disappearance to be 4.6 x 10 l.mole . sec , in excellent agreement with Paul and Dalby . He found that in the presence of excess O2, ozone was formed. He also spectroscopically detected NCO, a previously unidentified species which he assumed to be N2C2O or NCO2CN, and vi-brationally excited NO. To explain these results, he proposed the mechanism... 

Engleman, R., The vibrational state of hydroxyl radicals produced by flash photolysis of water-ozone-argone mixture. J Am Chem Soc 87., 4193, 1965. 

There is some controversy on the mechanism of ozone photodecomposition by UV light [367, 414, 643] but McGrath and Norrish [410, 455] identified 0(1D) atoms in the flash photolysis of Oa. 

Laser flash photolysis and discharge flow measurements of the reaction rates of OH with several VOC have been made in a project designed to provide data for the determination of the photochemical ozone creation potentials of the VOC. In related studies, the mechanisms of the atmospheric oxidation of a wide range of compounds have been developed. Finally, objective techniques for extensive mechanism reduction, first applied in combustion chemistry, have been applied to tropospheric mechanisms. 

We have employed laser flash photolysis coupled with laser-induced fluorescence (LP) and discharge flow (DF) coupled with LIF to study the rates of reaction of OH with a range of VOC. The compounds studied have significant emission rates and data are needed to determine their photochemical ozone creation potentials. 

McGrath, W.D. Norrish, R.G.W., 1960 Studies of the Reaction of Excited Oxygen Atoms and Molecules Produced in the Flash Photolysis of Ozone , in Proceedings of the Royal Society of London A, 254 317. 

---