where E disp n is the self-consistent D4 dispersion energy and E coul 3 the third-order on-site Coulomb energy. The GFN1-xTB energy expression has a similar structure but differs in the details of some energy contributions, for example, D3(BJ) dispersion is used instead of self-consistent D4 dispersion. For brevity, we will omit further details and refer the reader to the full theory and derivation of the xTB methods in Ref. 5.