Matrix isolation IR spectrum of CO2 in neon. Theoretical methods allow accurate prediction of the relative intensity and wavenumber at which the band occurs.
If a photon with suitable energy hits a molecule, various electronic, rotational and vibrational transitions can be stimulated in this molecule by absorption of the photon. This property of molecules is the reason for the ubiquitous greenhouse effect. Most of the radiation from the sun passes through our atmosphere, but the back radiation from earth, which is in the IR range, interacts with the molecules in our atmosphere. In current climate models, our atmosphere is greatly simplified. They only consider monomers that do not interact with each other. However, due to the very high local water content in the atmosphere, cluster formation is inevitable. These clusters show a different IR activity than the respective monomers, which leads to a change in the absorbed back radiation. Part of our research is aimed at modelling such effects using theoretical methods and subsequently confirming them experimentally.