Theory of dissociative electron attachment: Biomolecules and clusters

Department of Physics and Astronomy, University of Nebraska, Lincoln, NE 68588, USA

^a Corresponding author: ifabrikant1@unl.edu

Published online: 29 January 2015

Abstract

Very broad σ^∗ resonances, which are responsible for threshold structures and dissociative attachment in electron collisions with hydrogen halides, are also important in electron-impact bond-breaking in nucleobases and amino acids. We investigate this mechanism in more detail by carrying out model calculations of the N-H bond breaking in the uracil molecule. Although the σ^∗ resonance is extremely broad at the equilibrium nuclear geometry, it is stabilized fast when the N-H bond is stretched, and this produces a substantial dissociative attachment cross section. In addition, very pronounced vibrational Feshbach resonances are seen below vibrational excitation thresholds. To incorporate the effect of a cluster environment in the dissociative electron attachment process, we develop further the multiple scattering theory for this process and calculate the dissociative attachment cross section for the CF₃Cl molecule embedded in the (H₂O)₆ cluster.