Helium-induced electronic transitions in photo-excited Ba+-Hen exciplexes.
- Vindel Zandbergen P Laboratoire Collisions Agrégats Réactivité (LCAR), IRSAMC, Université de Toulouse, CNRS UMR 5589, Toulouse, France.
- Barranco M Laboratoire Collisions Agrégats Réactivité (LCAR), IRSAMC, Université de Toulouse, CNRS UMR 5589, Toulouse, France.
- Cargnoni F CNR-ISTM, Via Golgi 19, 20133 Milano, Italy.
- Drabbels M Laboratory of Molecular Nanodynamics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
- Pi M Departament FQA, Facultat de Física, Universitat de Barcelona, Barcelona, Spain.
- Halberstadt N Laboratoire Collisions Agrégats Réactivité (LCAR), IRSAMC, Université de Toulouse, CNRS UMR 5589, Toulouse, France.
- 2018-04-16
Published in:
- The Journal of chemical physics. - 2018
English
The possibility for helium-induced electronic transitions in a photo-excited atom is investigated using Ba+ excited to the 6p 2P state as a prototypical example. A diabatization scheme has been designed to obtain the necessary potential energy surfaces and couplings for complexes of Ba+ with an arbitrary number of helium atoms. It involves computing new He-Ba+ electronic wave functions and expanding them in determinants of the non-interacting complex. The 6p 2P ← 6s 2S photodissociation spectrum of He⋯Ba+ calculated with this model shows very weak coupling for a single He atom. However, several electronic relaxation mechanisms are identified, which could potentially explain the expulsion of barium ions from helium nanodroplets observed experimentally upon Ba+ photoexcitation. For instance, an avoided crossing in the ring-shaped He7Ba+ structure is shown to provide an efficient pathway for fine structure relaxation. Symmetry breaking by either helium density fluctuations or vibrations can also induce efficient relaxation in these systems, e.g., bending vibrations in the linear He2Ba+ excimer. The identified relaxation mechanisms can provide insight into helium-induced non-adiabatic transitions observed in other systems.
- Language
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- English
- Open access status
- green
- Identifiers
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- DOI 10.1063/1.5022863
- PMID 29655323
- Persistent URL
- https://sonar.ch/global/documents/281695
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