title: Electron transfer-induced fragmentation of thymine and uracil in atom-molecule collisions.
abstract: Ion-pair formation has been studied in hyperthermal (30-100 eV) neutral potassium collisions with gas phase thymine (C(5)H(6)N(2)O(2)) and uracil (C(4)H(4)N(2)O(2)). Negative ions formed by electron transfer from the alkali atom to the target molecule were analysed by time-of-flight (TOF) mass spectrometry. The most abundant product anions are assigned to CNO(-) and (U-H)(-)/(T-H)(-) and the associated electron transfer mechanisms are discussed. Special emphasis is given to the enhancement of ring breaking pathways in the present experiments, notably CNO(-) formation, compared with free electron attachment measurements.
authors.affiliation: Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: D
authors.initials: D
authors.lastname: Almeida
authors.forename: R
authors.initials: R
authors.lastname: Antunes
authors.forename: G
authors.initials: G
authors.lastname: Martins
authors.forename: S
authors.initials: S
authors.lastname: Eden
authors.forename: F
authors.initials: F
authors.lastname: Ferreira da Silva
authors.forename: Y
authors.initials: Y
authors.lastname: Nunes
authors.forename: G
authors.initials: G
authors.lastname: Garcia
authors.forename: P
authors.initials: P
authors.lastname: Limão-Vieira
mesh_terms: D004579:Electron Transport; D013058:Mass Spectrometry; D011188:Potassium / Q000737:chemistry; D013941:Thymine / Q000737:chemistry*; D014498:Uracil / Q000737:chemistry*
chemical_list: D014498:Uracil; D013941:Thymine; D011188:Potassium