Structures in dissociative electron attachment cross-sections in thymine, uracil and halouracils
Institute1 Institute2Laboratoire des Collisions Atomiques et Moléculaires (UMR 8625), Bâtiment 351, Université Paris-Sud, 91405 Orsay Cedex, France
Corresponding author: a email@example.com
Published online: 12 September 2005
The low energy parts (0–3 eV) of the dissociative electron attachment (DEA) cross-sections in uracil, thymine, and the halouracils 5-BrU, 5-ClU, 6-ClU, 5-FU, have been revisited with an improved energy resolution, focussing onto the puzzling structures observed on most cross-sections of the various anions fragments versus electron energy. The elastic electron scattering cross-sections near zero energy have also been recorded. In most cases they present a few features (cusps) related to the low energy peaks found in DEA cross-sections. Substantial differences are found in the detailed spectra of the fragments produced in 5-ClU and 6-ClU. Several interpretations already proposed to explain the previous observations, in terms of different thresholds and/or contributions of vibrational Feshbach resonances, and their limits, are discussed in the light of our new results. We expect that our more detailed results will stimulate theoretical work for a better understanding of the features observed.
PACS: 34.80.Ht – Dissociation and dissociative attachment by electron impact
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005