Simulation of forsterite protonation by the interatomic potential method

The interatomic potential method in an ionic approximation was used to model the protonation of forsterite crystals. The formation of isolated OH^? groups in iron-free and iron-bearing crystals and neutral clusters of protonated cation vacancies was considered. It was shown that the presence of trivalent impurities may significantly facilitate protonation processes owing to their reduction to a divalent state or formation of clusters with cation vacancies. In most cases, charge balancing of hydrogen-bearing defects by magnesium vacancies is energetically favorable over that involving silicon vacancies.