Gibbs free energy calculations about xtb

[haneug]

When you include the ALPB or the GBSA solvation model you already account for Gsolv in the total energy since this is included in your SCF. You can of course also use other (post-SCF) solvation models such as the CPCM-X. In this case, E should be calculated without solvation (so no alpb or gbsa) and then you can add Gsolv from CPCM-X. Note that the GFN methods are parameterized for geometries, frequencies, and non-covalent interactions and not for energies. So you might want to get your E from somewhere else (depending on your application/desired accuracy)