Including the slab into the matrix of stoichiometric coefficients leads to an equation that is similar to Eq. ( ), with an additional term -M H R f , which references enthalpies of formation to the ATcT thermochemical network. As shown previously in Section 4.2.2, M can conveniently be determined from N and N R via Eq. ( ). An alternative derivation of this approach was developed by Blöndal et al. , which relies on an adsorption reaction of the target species.