High Resolution Fourier Transform Spectroscopic Studies of the Atmospheric Sciences

Abstract

A program has been initiated in the Atmospheric Chemical Kinetics group in the NOAA Aeronomy laboratory to study the products of gas phase chemical reactions and high resolution spectra of transient species using a high resolution Fourier transform spectrometer (Bomem, Model DA3.002). A quantitative knowledge of gas phase reaction products is essential in order to develop a better understanding of chemical mechanisms important in atmospheric chemistry. The precise spectroscopic information obtained from our high resolution spectroscopic studies of transient species is used to obtain a better characterization of the physical properties of these species and also to provide the data neccessary to measure these species in both laboratory and atmospheric measurements. The Fourier transform experiment we have setup is similar in principle to smog chamber type experiments which have been used very successfully to analyze the stable products of gas phase reactions. The major differences between our apparatus and the smog chamber type are that we employ discharge flow techniques to prepare reactants in lieu of steady state photolysis, we operate at much lower pressures so that absorption lines are not significantly pressure broadened, and we can detect the radical reactants and products themselves, not just the stable products of the reactions.