title: Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase.
abstract: Collisions between O(3+) ions and neutral clusters of amino acids (alanine, valine and glycine) as well as lactic acid are performed in the gas phase, in order to investigate the effect of ionizing radiation on these biologically relevant molecular systems. All monomers and dimers are found to be predominantly protonated, and ab initio quantum-chemical calculations on model systems indicate that for amino acids, this is due to proton transfer within the clusters after ionization. For lactic acid, which has a lower proton affinity than amino acids, a significant non-negligible amount of the radical cation monomer is observed. New fragment-ion channels observed from clusters, as opposed to isolated molecules, are assigned to the statistical dissociation of protonated molecules formed upon ionization of the clusters. These new dissociation channels exhibit strong delayed fragmentation on the microsecond time scale, especially after multiple ionization.
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France). poully@ganil.fr.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Poully
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Violaine
authors.initials: V
authors.lastname: Vizcaino
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Lucas
authors.initials: L
authors.lastname: Schwob
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Rudy
authors.initials: R
authors.lastname: Delaunay
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Kocisek
authors.affiliation: Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA (UK).
authors.forename: Samuel
authors.initials: S
authors.lastname: Eden
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Chesnel
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Alain
authors.initials: A
authors.lastname: Méry
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Jimmy
authors.initials: J
authors.lastname: Rangama
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Lamri
authors.initials: L
authors.lastname: Adoui
authors.affiliation: CIMAP (UMR 6252)-CEA, CNRS, ENSICAEN, UCBN, Boulevard Henri Becquerel, BP 5133, 14070 Caen cedex 5 (France).
authors.forename: Bernd
authors.initials: B
authors.lastname: Huber
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory; D021241:Spectrometry, Mass, Electrospray Ionization; D013816:Thermodynamics
chemical_list: D000596:Amino Acids; D005740:Gases; D007477:Ions; D011522:Protons; D019344:Lactic Acid
keywords: amino acid clusters; fragmentation; highly charged ions; mass spectrometry; quantum-chemical calculations