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Collision-induced spectroscopy and spectral line shapes

Published: 15 October 2015

Collision-induced absorption is an important source of radiation trapping in planetary and stellar atmospheres where the concentration of polar molecules is low. Under these conditions, collisional complexes may dominate the absorption of infrared and microwave radiation. For example, the Jovian planets are massive and cool enough to have atmospheres with large concentrations of hydrogen and helium, and thus collision-induced absorption plays a big role.

Astronomers who model the radiation transfer in planetary atmospheres need to know the absorption for various gas mixtures of non-polar molecules. We obtain these absorption coefficients through computer simulations that are based on atomic- and molecular dynamics. We are also interested in fundamental line shape theory. Spectral line shapes tell us about underlying molecular interactions in a medium, and they can be used as a diagnostic tool in laboratory measurements.