Low-energy electron collisions with acetic acid

Abstract

We present cross sections for elastic collisions of low-energy electrons with acetic acid. We employed the Schwinger multichannel method with pseudopotentials in the static-exchange and static-exchange plus polarization approximations, for energies ranging from 0.1 to 10 eV. We found a ${\ensuremath{\pi}}^{\ensuremath{\ast}}$ shape resonance around 1.7 eV, corresponding to the ${A}^{\ensuremath{''}}$ symmetry of the ${C}_{s}$ group. This resonant state was assigned to the experimental dissociative electron attachment peak at 1.7 eV yielding ${\text{CH}}_{3}{\text{COO}}^{\ensuremath{-}}+\text{H}$. We also performed a series of electronic structure calculations using a small basis set for acetic, formic, and trifluoroacetic acids, which exhibit a similar behavior with respect to the dissociative electron attachment. We believe that hydrogen elimination triggered off by electron capture into a ${\ensuremath{\pi}}^{\ensuremath{\ast}}$ resonance could be a general property of carboxylic acids.