Dissociative recombination of isotopes with an ultra-cold electron beam from a superconducting electron cooler in a storage ring

Abstract

The dissociative recombinations of , , and were studied with an extremely low-temperature electron beam of the order of 1 meV produced by a superconducting electron cooler at the storage ring TARN II. The dissociative recombination spectra show a fine new structure and a clear isotope dependence in the low-energy region. Those features are well reproduced by the theoretical calculations based on a multichannel quantum-defect theory including rotational motion and discretized dissociative states. According to the theory, the newly observed structure is evidence for a new indirect mechanism where the intermediate states are not vibrationally excited Rydberg states but virtual dissociative states.