DFT Modeling of Isomerism of Doped Mg24L2 Clusters with Dopants L at the Surface and inside the Magnesium Cage

Abstract

The isomers of Mg24L2 nanoclusters with dopants L from the firt three periods (L = Li–Zn) in the exo- and endohedral positions of the magnesium cage have been calculated by the density functional theory (DFT) method. The effect of dopants on the structure, stability, and position on the energy scale has been studied. For the systems with atoms L = H, Li, Be N, Na, Co, and Cu, the “open” positions of dopants at the surface are more favorable, unlike their analogs with L = Be and B, for which the “closed” positions in the inner cavity of the cluster are more favorable and their promotion to the surface requires a significant energy input. For clusters with O, Si, P, S, and early 3d metal atoms, the differences in the energies of the exo- and endohedral isomers do not exceed a few kcal/mol. The atoms of the second half of the 3d series are characterized by their association into diatomic dopants L2. The results are compared with the data of similar DFT calculations of isomers of Al42L2 aluminum clusters with the same dopants L = Li–Zn and are of interest for modeling the mechanisms of catalytic hydrogenation of magnesium and aluminum nanoclusters at the molecular level.