title: Bond dissociation of the dipeptide dialanine and its derivative alanine anhydride induced by low energy electrons.
abstract: Dissociative electron attachment to dialanine and alanine anhydride has been studied in the gas phase utilizing a double focusing two sector field mass spectrometer. We show that low-energy electrons (i.e., electrons with kinetic energies from near zero up to 13 eV) attach to these molecules and subsequently dissociate to form a number of anionic fragments. Anion efficiency curves are recorded for the most abundant anions by measuring the ion yield as a function of the incident electron energy. The present experiments show that as for single amino acids (M), e.g., glycine, alanine, valine, and proline, the dehydrogenated closed shell anion (M-H)(-) is the most dominant reaction product. The interpretation of the experiments is aided by quantum chemical calculations based on density functional theory, by which the electrostatic potential and molecular orbitals are calculated and the initial electron attachment process prior to dissociation is investigated.
authors.affiliation: Institut für Ionenphysik and Angewandte Physik, and Center of Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: Elahe
authors.initials: E
authors.lastname: Alizadeh
authors.forename: David
authors.initials: D
authors.lastname: Gschliesser
authors.forename: Peter
authors.initials: P
authors.lastname: Bartl
authors.forename: Michaela
authors.initials: M
authors.lastname: Hager
authors.forename: Achim
authors.initials: A
authors.lastname: Edtbauer
authors.forename: Violaine
authors.initials: V
authors.lastname: Vizcaino
authors.forename: Andreas
authors.initials: A
authors.lastname: Mauracher
authors.forename: Michael
authors.initials: M
authors.lastname: Probst
authors.forename: Tilmann D
authors.initials: TD
authors.lastname: Märk
authors.forename: Sylwia
authors.initials: S
authors.lastname: Ptasińska
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Mason
authors.forename: Stephan
authors.initials: S
authors.lastname: Denifl
authors.forename: Paul
authors.initials: P
authors.lastname: Scheier
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives*; D000812:Anhydrides / Q000737:chemistry*; D004151:Dipeptides / Q000737:chemistry*; D004583:Electrons; D008958:Models, Molecular
chemical_list: D000812:Anhydrides; D004151:Dipeptides; C002956:alanylalanine; D000409:Alanine