Single points were performed with the semiempirical methods DFTB and AM1, as im-plemented in AMBER, and with ab initio DFT (PBE/DZVP level) using our GPU-enabled software LIO, compiled with AMBER16. Structures for which the singlepoint calculations did not converge were discarded. The embedding approximation for these QM/MM calculations was the electrostatic embedding for PBE and AM1 calculations, and a modified mechanical embedding for DFTB in which MM atomic charges are considered in the QM Hamiltonian (like in the electrostatic embedding) but the coupling term is calculated at the mechanical embedding level with Mulliken charges iteratively optimized within the self consistent field cycle. From the obtained electron densities in each case, Mulliken (AM1, DFTB and PBE) and CM3 (DFTB) atomic partial charges were determined.