Dissociative electron attachment to uracil deuterated at the N1 and N3 positions

Deuteration at the nitrogen sites of uracil produces a striking change in the dissociative attachment cross-section at electron energies below 3 eV. In particular, sharp structures observed in uracil are absent or too small to observe. This result, as well as theoretical modeling, supports the earlier assignment of the sharp structure to vibrational Feshbach resonances that decay by tunneling of the N1 hydrogen atom through the barrier created by the avoided crossing of the dipole bound anion potential surface by that of the lowest 2Σ valence anion state.