Vibrational Feshbach resonances in dissociative electron attachment to uracil

Abstract

Low-energy dissociative electron attachment to uracil molecules in the gas phase is partly controlled by interaction between the lowest ${\ensuremath{\sigma}}^{*}$ resonance with a dipole-supported anion state. We calculate this contribution using a combination of the finite element discrete model with the resonance $R$-matrix theory. Deuterated uracil is investigated, also, and a strong isotope effect is found. The results agree qualitatively and semiquantitatively with experimental data, but for a complete description of the process the interaction between a second N---H bond ${\ensuremath{\sigma}}^{*}$ resonance in the molecule and the second ${\ensuremath{\pi}}^{*}$ resonance should be included.