Dissociative ionization cross-sections and the rate coefficients of H 2 S, OCS, LiH, and SiC

Context . Electron-molecule and positron-molecule interactions play a major role in the interstellar medium. Although several inelastic channels have been studied in the literature, dissociative ionization studies of molecules are scarce. Aims . To calculate the dissociative ionization cross-sections of cations emerging from H 2 S, OCS, LiH, and SiC, we present the theoretical dissociative ionization cross-sections for the first time. Methods . We computed electron and positron impact ionization cross-sections using a semi-empirical binary encounter Bethe (BEB) method and we computed the partial ionization cross-sections (PICS) of cations using the mass spectrum dependence method coupled with BEB. We used the Relative and Absolute Partial Ionization and Dissociation cross-section code to calculate the dissociation energies. Results . We present our findings on the dissociation energies of cations, along with the electron impact the PICS of cations, the total electron-impact and direct positron-impact ionization cross-sections of neutral molecules (TICS and DICS), and the ionization rate coefficients of cations. Conclusions . The PICS calculations show a plausible agreement with the measured data for cations. In the case of dications, the present model fails to reproduce the experimental cross-sections. This study is the first to present Maxwellian rates for partial cross-sections.