Screening corrections for the interference contributions to the electron and positron scattering cross sections from polyatomic molecules

Highlights: • Interference terms for calculating molecular cross sections play an important role at low energies. • Interference terms have here been applied to the Screening Corrected Additivity Rule (SCAR+I). • SCAR+I results have been compared to an "exact" multicentre scattering calculation. • Integral and differential cross sections show improvement across the entire energy range. • SCAR+I eliminates inconsistencies between differential and integral cross sections values. An improvement of the screening-corrected Additivity Rule (SCAR) is proposed for calculating electron and positron scattering cross sections from polyatomic molecules within the independent atom model (IAM), following the analysis of numerical solutions to the three-dimensional Lippmann–Schwinger equation for multicenter potentials. Interference contributions affect all the considered energy range (1–300 eV); the lower energies where the atomic screening is most effective and higher energies, where interatomic distances are large compared to total cross sections and electron wavelengths. This correction to the interference terms provides a significant improvement for both total and differential elastic cross sections at these energies.