High resolution spectroscopy and applications

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Povey, Chad A
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Physics and Astronomy, 2013
With the ever increasing spectral resolution now achievable with modern spectrometers we do not just observe dark lines anymore but molecular absorption features at very high resolution. These features are governed by the kinematics of the molecules and can be examined carefully by using high resolution spectroscopy. A detailed description of the setup and performance of the tunable diode laser spectrometer (TDL) system used in my research is presented. This tunable laser system has been used to complete several high resolution line shape studies on the 1+ 2+ 4+ 5 and 1+ 3 combination bands of acetylene. The major focus of the presented results has been on the temperature dependence of the retrieved parameters and the identification of the best fitting line shape profile used in the present investigation. Improved spectral resolution also requires better understanding of its effects on the recorded data that could not have been observed on data obtained with low resolution instruments. One of these effects is known as line mixing and it occurs when neighbouring transitions interfere with each other causing a slight asymmetry in the spectral profile. In this Thesis I have examined the line mixing effect in CO2 spectra and the temperature dependence of these line mixing coefficients. The analysis is performed by using two common line mixing models; (1) the energy correct sudden approximation and (2) the exponential power gap law. Finally I will present a project based on the application of high resolution spectroscopy that involves monitoring N2O concentration at remote locations through the use of a long path gas cell and a tunable diode laser spectrometer system. The initial testing and setup of this monitoring system will be presented and discussed
xlii, 221 leaves : ill. ; 29 cm
Spectral resolution , Line mixing , High resolution spectroscopy , Tunable diode laser spectrometer , Absorption spectra , Dissertations, Academic