Theoretical study of isomerism of compounds of C-doped aluminum clusters Al13C2, TiAl12C2, and Al42C2

Abstract

Segments of the potential energy surfaces corresponding to isomers of the Al13C2, TiAl12C2, and Al42C2 clusters with two carbon atoms located in different positions at the surface and inside the Al13, TiAl12, and Al42 aluminum cages have been calculated by the density functional theory method. Their energies and structural and vibrational characteristics have been evaluated. Low-lying isomers with high-coordinated carbon atom C* have been localized. The energy parameters of Al13C2 have been refined in the coupled-cluster approximation. The effect of Ti doping on the relative energies of the isomers have been studied. The results for the small Al13C2 and TiAl12C2 clusters have been compared with the calculations of the related clusters Al13L and TiAl12L, where L = C2H2, CO, CO2, and N2. For the bulkier Al42C2 cluster, it has been shown that five- and six-coordinate configurations are typical of the C* atoms located both at the periphery and in the inner “core” of the Al42 cage.