Reaction enthalpy of a stoichiometrically balanced reaction (gas-phase, surface, and adsorption reaction) calculated from enthalpies of formation. This quantity is free of any anchor/reference species. ∆ r H QM Enthalpy of reaction j calculated only from DFT energies (∆ r H QM = ∑ ν i E i ) ν Stoichiometry vectors with stoichiometry coefficients ν i of each species i in a reaction M Stoichiometry matrix that encompasses a set of stoichiometry vectors (species × references) N