Molecular Physics seminar

From spectroscopy to collisions: Photoionization of vibrationally excited H2 molecules

by Zsolt Mezei (Laboratoire Aime-Cotton, CNRS/Universite Paris Sud, Bat. 505, F-91405, Orsay, France)

FA31 ()


Diatomic molecular hydrogen is the dominant molecule in the interstellar molecular clouds. The modelling of these environments relies on accurate cross sections for the various relevant processes. Among them, the photoionization plays a major role in the kinetics and in the energy exchanges involving H2. The recent discovery of vibrationally excited molecular hydrogen in extragalactic environments revealed the need for new accurate evaluation of the cross sections of photoionization from the relevant excited levels. In my talk I will describe the calculation of the relevant observables such as transition energies, absolute intensities, spontaneous emission probabilities and photoionization cross sections. The treatment is based on multi-channel quantum defect theory combined with frame transformation. This work shows that resonance effects are far more important than previously assumed.