Laboratory spectroscopic study of acetylene and carbon dioxide for atmospheric remote sensing purposes

Abstract

This thesis presents line-shape studies of carbon dioxide and acetylene, found as trace constituents in planetary atmospheres. The v1+v3 band of acetylene broadened by CO2 was recorded using a tunable diode laser spectrometer at different pressures (50-750 Torr) and temperatures (216-333 K) to retrieve pressure induced line-shape parameters as well as their temperature dependences. A second study was carried out to analyze line shapes of the Q-branch transitions of three weak bands (12201-03301, 11101-10002 and 12201-11102) of pure CO2 recorded at room temperature and different pressures (0.2-140 Torr) using a Fourier transform spectrometer. For both of these studies a non-linear least squares fitting software was used. A constraint analysis was performed in the CO2 study in order to reduce correlations between the retrieved line-shape parameters. Furthermore, theoretical calculation of line mixing parameters corresponding to the three bands of CO2 was performed using Exponential Power Gap (EPG) law.