𝑛 , = ∑ 𝛽 , 𝑛 , and 𝑛̇ , = ∑ 𝛽 , 𝑛̇ , (7) With 𝑛 , and 𝑛 , as the molar amount of species 𝑖 and element ℎ on the surface and 𝛽 , as the number of atoms of element ℎ in species 𝑖 . More detailed information on the evaluation is described by Meyer et al. .