title: Absolute total and partial dissociative cross sections of pyrimidine at electron and proton intermediate impact velocities.
abstract: Absolute total non-dissociative and partial dissociative cross sections of pyrimidine were measured for electron impact energies ranging from 70 to 400 eV and for proton impact energies from 125 up to 2500 keV. MOs ionization induced by coulomb interaction were studied by measuring both ionization and partial dissociative cross sections through time of flight mass spectrometry and by obtaining the branching ratios for fragment formation via a model calculation based on the Born approximation. The partial yields and the absolute cross sections measured as a function of the energy combined with the model calculation proved to be a useful tool to determine the vacancy population of the valence MOs from which several sets of fragment ions are produced. It was also a key point to distinguish the dissociation regimes induced by both particles. A comparison with previous experimental results is also presented.
authors: Instituto de Física, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ, Brazil.
authors: Wania
authors: W
authors: Wolff
authors: Instituto de Física, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ, Brazil.
authors: Hugo
authors: H
authors: Luna
authors: Instituto de Física, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ, Brazil.
authors: Lucas
authors: L
authors: Sigaud
authors: Departamento de Física, Pontificia Universidade Católica do Rio de Janeiro, PO 38071, Rua Marquês de São Vicente 225, 22453-900 Rio de Janeiro, RJ, Brazil.
authors: Andre C
authors: AC
authors: Tavares
authors: Instituto de Física, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ, Brazil.
authors: Eduardo C
authors: EC
authors: Montenegro
mesh_terms: D004583:Electrons; D007477:Ions / Q000737:chemistry; D011522:Protons; D011743:Pyrimidines / Q000737:chemistry*
chemical_list: D007477:Ions; D011522:Protons; D011743:Pyrimidines; C030986:pyrimidine