Thermal Stability of Endohedral First-Row Transition-Metal TM@ZniSi Structures, i = 12, 16

Abstract

The thermal stability of first-row transition-metal-doped TM@ZniSi nanoclusters, in which TM stands for the first-row transition metals from Sc to Zn and i = 12, 16, has been analyzed for the two lowest-lying spin states of each metal. These structures were previously characterized by Matxain et al. (Chem.—Eur. J.2008, 14, 8547). We have seen that the metal atom can move toward the surface of the nanocluster, forming the so-called surface-doped structure. Hence, we have calculated the relative energies between these two isomers. Additionally, we have also characterized the transition states connecting both isomers and the energy barriers needed to move from one to another in order to predict the thermal stability of the endohedral compounds. These values are further used to predict the lifetimes of the endohedrally doped nanoclusters. Most of the lifetimes are predicted to be very small, although most of them are large enough for experimental detection. Conversely, the lifetimes of Zn@Zn12S12 and Zn@Zn16S16 have proved to be very large.