Molecular Physics seminar

Reactive collisions of electrons with molecular cations: major mechanisms,relevant interactions, and comparison between computed and measured rate coefficients

by Prof. Ioan Schneider (University of Le Havre, France)

FA32 ()


The dissociative recombination, the ro-vibrational excitation (de-excitation) and the dissociative excitation of molecular cations: AB+ + e? ? A + B, AB+ + e?, A + B+ + e? play a major role in the kinetics and in the energy transfer of numerous ionized cold environments ? interstellar molecular clouds, planetary atmospheres, combustion flames, plasmas involved in surface processing, hypersonic entry of spacecrafts and edge of fusion devices. The measurement of their rate coefficients using storage-rings reached a remarkable precision.On the theoretical side, we are presently able to describe efficiently the interference between the major mechanisms ? direct and indirect ? including in the analysis the contribution of numerous series of valence and Rydberg states of resonant capture. We do this within an approach based on the multichannel quantum defect theory (MQDT), taking into account the ro-vibrational structure of the ion and of the neutral system. Our results on several diatomic species - H2 and its isotopes, NO, CH, CF and CO ? will be illustrated, for a broad range of energies and target states.The perspectives on the developments and extensions of our methods and on the approach of novel systems, as well as the possibilities of collaboration with the Stockholm team, will be invoked.