title: Shape resonances in low-energy-electron collisions with halopyrimidines.
abstract: We report calculated cross sections for elastic collisions of low-energy electrons with halopyrimidines, namely, 2-chloro, 2-bromo, and 5-bromopyrimidine. We employed the Schwinger multichannel method with pseudopotentials to compute the cross sections in the static-exchange and static-exchange plus polarization levels of approximation for energies up to 10 eV. We found four shape resonances for each molecule: three of π* nature localized on the ring and one of σ* nature localized along the carbon-halogen bond. We compared the calculated positions of the resonances with the electron transmission spectroscopy data measured by Modelli et al. [J. Phys. Chem. A 115, 10775 (2011)]. In general the agreement between theory and experiment is good. In particular, our results show the existence of a π* temporary anion state of A2 symmetry for all three halopyrimidines, in agreement with the dissociative electron attachment spectra also reported by Modelli et al. [J. Phys. Chem. A 115, 10775 (2011)].
authors: Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-990 Curitiba, Paraná, Brazil.
authors: Alessandra Souza
authors: AS
authors: Barbosa
authors: Márcio H F
authors: MH
authors: Bettega
mesh_terms: D003198:Computer Simulation; D004583:Electrons; D054879:Halogenation; D008958:Models, Molecular; D011743:Pyrimidines / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D011743:Pyrimidines