Investigating resonant low-energy electron attachment to formamide: dynamics of model peptide bond dissociation and other fragmentation channels

TL;DR

This study combines experimental momentum imaging and theoretical analysis to explore how low-energy electrons attach to formamide, leading to peptide bond dissociation and various fragmentation pathways.

Contribution

It provides detailed experimental momentum data and theoretical insights into the electron attachment mechanisms and fragmentation channels in formamide.

Findings

Identification of angular and kinetic energy distributions for fragments

Evidence supporting a Feshbach resonance at ~6 eV

Analysis of multiple dissociation pathways

Abstract

We report experimental results on three-dimensional momentum imaging measurements of anions generated via dissociative electron attachment to gaseous formamide. From the momentum images, we analyze the angular and kinetic energy distributions for NH$_2^{-}$, O$^{-}$, and H$^{-}$ fragments and discuss the possible electron attachment and dissociation mechanisms for multiple resonances for two ranges of incident electron energies, from 5.3~eV to 6.8~eV, and from 10.0~eV to 11.5~eV. {\it Ab initio} theoretical results for the angular distributions of the NH$_2^{-}$ anion for $\sim$6~eV incident electrons, when compared with the experimental results, strongly suggest that one of the two resonances producing this fragment is a $^2$A$''$ Feshbach resonance.