A molecular beam scattering study of the weakly bound complexes of water and hydrogen sulphide with the main components of air

Abstract

Total integral cross-section experiments on the collisions of rotationally hot water and hydrogen sulphide projectiles with O₂ and N₂ targets are reported for the first time. The experimental data allowed the determination of the effective potential energy curves, which are representative of the intermolecular interactions averaged over all possible relative configurations of these weakly bound complexes. Such information is relevant for the modelling of elementary processes occurring in planetary atmospheres. These experimental determinations were also used to test the accuracy of the intermolecular interactions provided by ab initio calculations, recently available for water-containing complexes. We further investigated possible experimental effects due to interaction components other than van der Waals and some evidence was found for the complexes of water, whereas these effects appear to be below the experimental sensitivity for the hydrogen-sulphide-containing complexes.

Keywords:

• water
• molecular interactions
• oxygen
• nitrogen

Acknowledgements

This research was supported by the Italian Ministero per la Ricerca Scientifica through PRIN project No. 2008KJX4SN_003. L.F.R. gratefully acknowledges PhD support from the EU programme Alban.