Dynamics of dissociative electron attachment to model peptides*

Consider formamide, methylated formamides, and acetamide as prototypical molecules for the study of electron-capture-induced peptide bond breaking in protein or amino acid chains. The fundamental dynamics of dissociative electron attachment to simple amides is investigated by measuring the kinetic energy and angular distributions of anion fragments, using a momentum imaging reaction microscope. Transient anions are formed by electron attachment to molecules in an effusive beam, with a probability that is highly-dependent on the initial orientation of the target molecule[1]. In some cases, the experimental results reveal highly structured fragment angular distributions, offering direct insight into the symmetry of the resonances. At the lowest electron attachment energies in the experiments on formamide, the fragments dissociate with low kinetic energy, and the angular distributions have much broader structures[2]. These measurements are analyzed and informed by ab initio electron scattering calculations for two Feshbach resonances, indicating O-C-N opening dynamics for the lowest energy resonance.