Theoretical Modeling of Exo- and Endohedral Hydrogenation Reactions of the Doped Magnesium Cluster Mg17Ni

AbstractBased on DFT and IRC calculations, the potential energy surfaces of the hydrogenation channels of the Mg17Ni cluster have been compared. In “exohedral” channels, sorption, post-sorption, and migration processes of H atoms are assumed to be localized on the cage surface with maximum barriers of ~14 kcal/mol. In the “endohedral” channel with a barrier of ~6 kcal/mol, the key role is played by transformations of the planar configuration of the surface NiH4 group into a tetrahedral one, in which two of its lower H atoms migrate through the inner cavity and enter surface positions, inverting through the square and adjacent triangular faces into the lower half of the cage. The course of the latter process requires milder conditions in comparison with exohedral channels.