10.26165/JUELICH-DATA/DNGQOQ Grooß, Jens-Uwe0000-0002-9485-866X(Forschungszentrum Jülich) Jülich DATA 2025 This data set is part of the study by Grooß et al. (2025). In this study, a discrepancy between model simulations and observations of HCl in the dark polar stratosphere (see here) is further investigated. Adding futher reactions to the standard model chemistry, especially the heterogeneous reaction of chlorine peroxide (Cl2O2) with hydrogen chloride (HCl) helps reducing this reported discrepancy significantly. Grooß, Jens-Uwe(Forschungszentrum Jülich)