Exploring high-energy doubly excited states of NH by dissociative recombination of NH+
2014 (English)In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 47, no 3, 035201- p.Article in journal (Refereed) Published
We have investigated electron capture by NH+ resulting in dissociative recombination (DR). The impact energies studied of similar to 4-12 eV extend over the range below the two lowest predicted NH+ dissociative states in the Franck-Condon (FC) region of the ion. Our focus has been on the final state populations of the resulting N and H atoms. The neutral DR fragments are detected downstream of a merged electron and ion beam interaction zone in the TSR storage ring, which is located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Transverse fragment distances were measured on a recently developed high count-rate imaging detector. The distance distributions enabled a detailed tracking of the final state populations as a function of the electron collision energy. These can be correlated with doubly excited neutral states in the FC region of the ion. At low electron energy of similar to 5 eV, the atomic product final levels are nitrogen Rydberg states together with ground-state hydrogen. In a small electron energy interval near 7 eV, a significant part of the final state population forms hydrogen Rydberg atoms with nitrogen atoms in the first excited (D-2) term, showing the effect of Rydberg doubly excited states below the predicted 2(2)Pi ionic potential. The distance distributions above similar to 10 eV are compatible with nitrogen Rydberg states correlating to the doubly excited Rydberg state manifold below the ionic 2(4) Sigma(-) level.
Place, publisher, year, edition, pages
Bristol: Institute of Physics Publishing (IOPP), 2014. Vol. 47, no 3, 035201- p.
dissociative recombination, doubly excited molecular states, molecular collisions
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:su:diva-101002DOI: 10.1088/0953-4075/47/3/035201ISI: 000330215600006OAI: oai:DiVA.org:su-101002DiVA: diva2:699704
Max Planck Society; CAS- MPS Doctoral Training program; National Natural Science Foundation of China 1117901, 11275240; National Basic Research Program of China 2010CB832901; Weizmann Institute of Science; NSF Division of Astronomical Sciences Astronomy and Astrophysics Grants program; NASA Astronomy and Physics Research and Analysis Program; COST Actio;n CM0805 DFG Priority Program 1573. 2014-02-282014-02-212014-02-28Bibliographically approved