A series of computations based on multichannel quantum defect theory have been performed in order to produce the cross sections of rotational transitions (excitationsto 10) and of their competitive process, the dissociative recombination, induced by collisions of HD + ions with electrons in the energy range 10 −5 to 0.3 eV. Maxwell anisotropic rate coefficients, obtained from these cross sections in the conditions of the Heidelberg Test Storage Ring (TSR) experiments (k B T t = 2.8 meV and k B T l = 45 μeV), have been reported for those processes in the same electronic energy range. Maxwell isotropic rate coefficients have been presented as well for electronic temperatures up to a few hundred Kelvins. Very good overall agreement is found between our results for rotational transitions and the former theoretical computations as well as with experiment. Furthermore, due to the full rotational computations performed, the accuracy of the resulting dissociative recombination cross sections is improved considerably.

We report calculations of H 2 − states using a variational R-matrix approach combined with multichannel quantum defect theory. Several Rydberg series converging to the 2pπ state of the H + 2 ion core are established and their mutual channel interactions characterized. The influence of the external electron on the chemical bond is found to be particularly strong in these electronically and chemically weakly bound states.

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