Research Projects

Huge amounts of the volatile organic compounds are released into the Earth's atmosphere out of which the lower hydrocarbons take the major stake. Crigee Intermediates (CI) are very important transient species in the Earth's atmosphere. Cis are formed in the atmosphere due to the reactions of ozone with unsaturated hydrocarbons. As the concentrations of the hydrocarbons are very large, the CIs can also form in high concentrations. They also play a very important role in deciding the fate of VOC's and hence their lifetimes. The present project conducted investigation using sophisicated spectroscopic tools such as cavity ring down spectroscopy. This investigation would help in understanding the mechanism of the reactions of CIs with variety of compounds in the atmosphere. This initiative would also provide the kinetic parameters and optical properties such as absorption cross sections and quantum yeilds which in turn would help in modeling the chemical composition of the Earth's atmosphere

A collinear Cavity Rig Down Spectrometer was established where tens of kilometers of optical pathlength can be established. The built-in spectrometer was used to study the reactions of Criegee Intermediates with important VOCs (carbonyl compounds, in particular) relevant to the Earth’s atmosphere. The Criegee Intermediates play a very significant role in the Earth’s troposphere, where emission of olefinic compounds is large, particularly in the urban/industrially developed areas. As the lifetimes of these olefines are significant, they live long and can be transported from these regions to others. The deliverable of this project can be used by the modelers in both climate change and aerosol chemistry. Therefore, the Criegee Intermediates compete with OH radicals to react with the available