Executive Summary : | Large amounts of Volatile Organic Compounds (VOCs) are released into the Earth’s atmosphere, and they get oxidized with the oxidizing agents such as OH radicals, Cl atoms, NOx and ozone. The primary radical that is formed in the oxidation is usually an Alkyl/Aryl/Allyl type. As they are formed in the oxygen rich environment, they readily form peroxy radicals, RO₂ (R=Alkyl, Aryl and Allyl). The RO₂ radicals play a very important role in the Earth’s troposphere as well as low temperature combustion. The RO₂ radicals oxidizes NO to NO₂ radicals, and they would further get involved in the photochemistry to form ozone in the troposphere. On the other hand, the RO radical that is formed in the process of oxidation of NO by RO2 would further form ozone in its secondary oxidation process. At this juncture, it is important to note that, the concentration of the peroxy radicals (RO₂) is comparable with that of hydroxyl radicals (OH). Therefore, the OH radical chemistry with peroxy radicals play a very significant role in the Eart’s troposphere in terms of the formation of varieties of secondary volatile organic compounds (SVOCs). Thus formed SVOCs show significant influence on the chemical composition and thereby climate. Therefore, it is very essential to measure the kinetics of these two short-lived and important radicals to understand the radical radial chemistry. Such measurements can be done only with highly sophisticated and supersensitive optical spectroscopic methods such as Cavity Ring Down Spectroscopy (CRDS) and Laser Induce Fluorescence (LIF). However, as the concentrations of these two radicals to be mimicked should be same, one must use both such spectroscopic techniques to simultaneously and independently measure the kinetics. Therefore, the key point of this proposal is to integrate both CRDS and LIF techniques and measure the kinetics of the selective peroxy radicals now and many more in future using this facility. |