Electron and Positron Scattering by the Formamide Molecule.

We report calculated elastic integral, differential, and momentum transfer cross sections for electron and positron collisions with the formamide (HCONH2) molecule, for impact energies up to 10 eV. We have used the Schwinger multichannel method in the static-exchange and static-exchange plus polarization approximation for collisions of electrons and the static plus polarization approximation for collisions of positrons. The Born-closure procedure was applied to account for the long-range potential due to the permanent dipole moment of formamide. We obtained the well-characterized π* shape resonance located at around 2.38 eV, which belongs to the A″ symmetry of the Cs point group. Our integral and differential cross sections for collisions of electrons were compared with the data available in the literature and showed a good qualitative agreement. To the best of our knowledge, no experimental and theoretical data are currently available for positron-formamide collision, so our present cross sections were compared with the cross sections of formic acid, which is also polar and is isoeletronic to formamide.