Electron and Positron Scattering by Formamide Molecule.

We report calculated elastic integral, differential and momentum transfer cross sections for electron and positron collisions with the formamide (HCONH<u>2</u>) 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 C<u>s</u> 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.