Dissociative electron attachment to acetylene

Abstract

The mechanism and cross section for dissociative electron attachment of acetylene after collision with electrons in the 0--7 eV range is reported. The positions of the resonances and the autoionization widths are determined by electron scattering calculations using the complex Kohn variational method. The complex potential energy surface relevant to the metastable negative ion ${\text{C}}_{2}{\text{H}}_{2}^{\ensuremath{-}\ensuremath{\ast}}$ is constructed as a function of the $\text{C}\ensuremath{\equiv}\text{C}$ and C--H stretches and the CCH angle. The lowest resonant potential is then used as input for the study of the dissociation dynamics within the local complex potential model using the multiconfiguration time-dependent Hartree method. The calculated dissociative electron attachment cross section as a function of electron energy is compared to available experimental findings.