title: Potassium-uracil/thymine ring cleavage enhancement as studied in electron transfer experiments and theoretical calculations.
abstract: We report experimental and theoretical studies on ring cleavage enhancement in collisions of potassium atoms with uracil/thymine to further increase the understanding of the complex mechanisms yielding such fragmentation pathways. In these electron transfer processes time-of-flight (TOF) negative ion mass spectra were obtained in the collision energy range 13.5-23.0 eV. We note that CNO(-) is the major ring breaking anion formed and its threshold formation is discussed within the collision energy range studied. Such a decomposition process is supported by the first theoretical calculations to clarify how DNA/RNA pyrimidine base fragmentation is enhanced in electron transfer processes yielding ion-pair formation.
authors.affiliation: Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal.
authors.forename: D
authors.initials: D
authors.lastname: Almeida
authors.forename: M-C
authors.initials: MC
authors.lastname: Bacchus-Montabonel
authors.forename: F Ferreira
authors.initials: FF
authors.lastname: da Silva
authors.forename: G
authors.initials: G
authors.lastname: García
authors.forename: P
authors.initials: P
authors.lastname: Limão-Vieira
mesh_terms: D004247:DNA / Q000737:chemistry; D004579:Electron Transport; D011188:Potassium / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry; D011789:Quantum Theory; D012313:RNA / Q000737:chemistry; D013941:Thymine / Q000737:chemistry*; D014498:Uracil / Q000737:chemistry*
chemical_list: D011743:Pyrimidines; D014498:Uracil; D012313:RNA; D004247:DNA; C030986:pyrimidine; D013941:Thymine; D011188:Potassium