The absolute dissociative recombination and absolute dissociative excitation rate coefficients and cross sections have been determined for N2+ and electrons for collision energies between 10 meV and 30 eV. The ion storage ring CRYRING has been used in combination with an imaging technique with a position-and-time-sensitive detector. Information is retrieved on the ion beam vibrational state populations and on the product branching in the dissociative recombination process at 0 eV collisions. A hollow cathode ion source has been used to lower the vibrational excitation in the ion beam; a more traditional hot-cathode ion source was used as well. The most important findings are the following. The rate coefficient for an N2+ ion beam (46%, v=0, 27% v=1) versus electron temperature (K) is α(Te)=1.75(±0.09)×10−7(Te/300)−0.30 cm3 s−1. The dissociative recombination rate is found to be weakly dependent on the N2+ vibrational level. At 0 eV collision energy, the v=0 product branching is found to be 0.37(8):0.11(6):0.52(4) for N(4S)+N(2D):N(2P)+N(4S):N(2D)+N(2D) fragments. The dissociative recombination cross section does not have a high-energy peak as was found in a number of lighter molecular systems. The dissociative excitation signal starts only slightly above the energy threshold for dissociation, and peaks near 25 eV. From the dissociative excitation data and literature data, information is retrieved on the dissociative ionization of N2+. The comparison of these results with earlier DR measurements is extensively discussed.

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A theoretical treatment of dissociative recombination (DR), vibrational excitation (VE) and vibrational deexcitation (VdE) of the BeH + ion in its four lowest vibrational states (X 1 Σ + , v + i = 0, 1, 2, 3) is reported. The multichannel quantum defect theory is used to determine cross sections and rate coefficients. Three electronic symmetries of BeH-2 Π, 2 Σ + , and 2 ∆-have been included in the calculations. At low energies the DR is dominated by capture into states of 2 Π symmetry. Satisfactory agreement with results obtained using the wave packet approach is reached at intermediate energies despite significant differences at low energies. Cross sections and rate coefficients suitable for the modeling of the kinetics of BeH + in fusion plasmas and in the stellar atmospheres are presented and discussed.

The direct mechanism of dissociative recombination of HF + is studied using both time-dependent and time-independent methods, where the dynamics on 30 resonant states is explored. The relevant electronic states are calculated ab initio by combining electron scattering calculations with multireference configuration interaction structure calculations. For collision energies between 0.04 and 10 eV, we obtain qualitative agreement with experiment. At 1.9 eV there is a sharp threshold in both the experimental and theoretical cross sections that can be explained by the opening of new asymptotic limits. The measured cross section below 0.04 eV is not reproduced due to the neglect of the electronic couplings between the neutral states. We examine the validity of the local approximation for treating autoionization from the resonant states included in this study.