For reparameterization of GFN1-xTB, we used the Clusteromics I-V data sets containing (acid) 0-2 (base) 0-2 clusters of the following atmospherically relevant species: sulfuric acid (SA), methanesulfonic acid (MSA), nitric acid (NA), formic acid (FA), ammonia (AM), methylamine (MA), dimethylamine (DMA), trimethylamine (TMA) and ethylenediamine (EDA). All structures are optimized at the ωB97X-D/6-31++G(d,p) level of theory and we used the up to three lowest electronic energy configurations found per each cluster as the optimization set for GFN1-xTB reparametrization. This leads to an optimization set comprising a total of 1073 clusters. The GFN1-xTB reparameterization based on this optimization set will be denoted as the AMC-xTB model.