Ab initio computation of the broadening of water rotational lines by molecular hydrogen

Laurent Wiesenfeld (1) , Alexandre Faure (1)

1 LAOG - Laboratoire d'Astrophysique de Grenoble

Theoretical cross sections for the pressure broadening by hydrogen of rotational transitions of water are compared to the latest available measurements in the temperature range 65-220 K. A high-accuracy interaction potential is employed in a full close-coupling calculation. A good agreement with experiment is observed above similar to 80 K, while the sharp drop observed experimentally at lower temperatures is not predicted by our calculations. Possible explanations for this discrepancy include the failure of the impact approximation and the possible role of ortho-to-para conversion of H-2.

Domaines: Optique [physics.optics]

Laurent Wiesenfeld, Alexandre Faure. Ab initio computation of the broadening of water rotational lines by molecular hydrogen. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2010, 82, pp.040702. ⟨10.1103/PhysRevA.82.040702⟩. ⟨hal-00631984⟩