Rotational Cooling ofHD+Molecular Ions by Superelastic Collisions with Electrons

D. Shafir, S. Novotny, H. Buhr, S. Altevogt, A. Faure, M. Grieser, A. G. Harvey, O. Heber, J. Hoffmann, H. Kreckel, L. Lammich, I. Nevo (+7 others)
2009 Physical Review Letters  
Merging an HD þ beam with velocity matched electrons in a heavy ion storage ring we observed rapid cooling of the rotational excitations of the HD þ ions by superelastic collisions (SEC) with the electrons. The cooling process is well described using theoretical SEC rate coefficients obtained by combining the molecular R-matrix approach with the adiabatic nuclei rotation approximation. We verify the ÁJ ¼ À2 SEC rate coefficients, which are predicted to be dominant as opposed to the ÁJ ¼ À1
more » ... to the ÁJ ¼ À1 rates and to amount to ð1-2Þ Â 10 À6 cm 3 s À1 for initial angular momentum states with J 7, to within 30%.
doi:10.1103/physrevlett.102.223202 pmid:19658863 fatcat:yqnpw3ymnbhtbiotm2nc4iug4u