Abstract
A valence shell study of electrosprayed insulin protein polyanion photodetachment was carried out on a vacuum ultra-violet synchrotron radiation beamline coupled to a radiofrequency ion trap, for both close- and open-shell species. A two-electron photodetachment is observed, which arises from two different mechanisms that are disentangled: a sequential multi-photon absorption and a direct one-photon two-electron process. The threshold for the direct double-electron ejection is measured at 11.4 eV and corresponds to electronic excitation in the valence shell, which makes it the first observation of direct double photodetachment in the valence shell. The results are discussed in the light of previous knowledge from multiple photoionization and ab initio calculations on model polyanions. Double photodetachment appears to be a relaxation mechanism that leads to oxidized anions of striking stability, a feature of high relevance in radiobiology.
Highlights
Double photodetachment appears to be a relaxation mechanism that leads to oxidized anions of striking stability, a feature of high relevance in radiobiology
Ions appearing at one-half the mass-to-charge ratio of the parent atomic or molecular ions in conventional mass spectrometry were correctly identified as doubly charged ions, usually the relative abundances of these ions are low
The only measurements of double photodetachment (DPD) on molecular anions concern an innervalence DPD study of CN−, in the 25–90 eV energy range, for which the main relaxation mechanism has been identified as inner-valence autoionization of excited CN− leading to CN+ [21] and of multiply charged C60 anions [22]
Summary
To cite this version: Claire Brunet, Rodolphe Antoine, Philippe Dugourd, Denis Duflot, Francis Canon, et al. Valence shell direct double photodetachment in polyanions. New Journal of Physics, Institute of Physics: Open Access Journals, 2013, 15 (6), pp.3024. HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés
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