Ionization study of cyanopolyynes HC_nN (n=1–17) by electron and positron impact

Abstract In this work, we investigate how electrons and positrons interact with important space molecules, specifically cyanopolyynes HC n N(n=1-17). These are linear molecules detected in the interstellar medium (ISM) and observed in regions like Sgr B2, Taurus Molecular Cloud -1 (TMC-1), the circumstellar envelope of the carbon star IRC +10216, and cold molecular clouds. We apply the binary-encounter Bethe (BEB) model to determine the ionization cross sections for both electron and positron impacts on these molecules, covering an energy range from ionization threshold to 5 keV. These molecules play a crucial role in astrophysics, astrochemistry, and atmospheric studies. However, their data are limited, particularly concerning positron impact ionization, which is being calculated for the first time in this study. Due to the complexity of these molecules, experimental data are lacking and only a small amount of theoretical information is currently available. Additionally, we have calculated properties like polarizability, dipole moment and highest occupied molecular orbital (HOMO) energy for these molecules. We have also studied the correlation of the maximum ionization cross section with the polarizability and ionization energy of the targets. These data are important for understanding cyanopolyynes and will help scientists model chemical processes in space.