title: Dehalogenation of 5-halo-uracil molecules induced by 100 keV proton collisions.
abstract: Neutral and cationic halogen loss of singly and doubly ionised 5-X-uracil (X = F, Cl, Br, I) after collisions with 100 keV protons have been studied in the gas phase. The rates of these dissociation channels are strongly dependant on the nature of the halogen substituent. It is very weak in the case of fluorine but is a dominant channel for iodine. Dissociation mechanisms are proposed for a number of significant channels associated to dehalogenation. It is suggested that some final ion products originate from specific processes. For instance, ion products of mass 38, 39 and 40 amu are very sensitive to the nature of the primarily ejected halogen and result from pathways associated to dehydrogenation and transient formation of the dehalogenated uracil cation.
authors.affiliation: aLaboratoire Collisions Agrégats Réactivite, IRSAMC, Université de Toulouse, UPS, CNRS, F-31062 Toulouse, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Champeaux
authors.forename: Pierre
authors.initials: P
authors.lastname: Çarçabal
authors.forename: Julien
authors.initials: J
authors.lastname: Rabier
authors.forename: Pierre
authors.initials: P
authors.lastname: Cafarelli
authors.forename: Martine
authors.initials: M
authors.lastname: Sence
authors.forename: Patrick
authors.initials: P
authors.lastname: Moretto-Capelle
mesh_terms: D005740:Gases / Q000737:chemistry; D006219:Halogens / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D013058:Mass Spectrometry; D011522:Protons; D013816:Thermodynamics; D014498:Uracil / Q000737:chemistry*
chemical_list: D005740:Gases; D006219:Halogens; D007477:Ions; D011522:Protons; D014498:Uracil