Since there is no explicit contribution accounting for spin-polarization, all xTB methods energetically favor low-spin solutions, even if the physical ground state would have a higher multiplicity. To overcome this limitation, spin-polarization can be explicitly introduced in the Hamiltonian, allowing xTB to recover high-spin ground states correctly. Additional energy contributions are the effective nuclear repulsion E rep 0 and London dispersion E disp n . The short-ranged nuclear repulsion function parameterizes the combination of nuclear-nuclear repulsion E nn , the nuclearelectron attraction of the atomic densities V ext [ρ 0 ], and Coulomb repulsion of the atomic densities J[ρ 0 ]. The final GFN2-xTB energy is given as,