Structure and Stability of the Endohedrally Doped (X@CdS) X=Na,K,Cl,Br Nanoclusters.

Abstract

Endohedral (X@CdiSi)q=0,±1 structures have been characterized by means of the density functional theory with X being alkali metals such as Na and K or halogens such as Cl and Br and with i = 4, 9, 12, 15, 16. These nanoclusters have been chosen because of their high sphericity, which is known to be one of the parameters determining the stability of the endohedral nanoclusters, along with the charge and size of the guest atom. In these structures, the atoms are trapped inside previously characterized spheroid hollow structures with positively charged Cd atoms and negatively charged S atoms. Moreover, although the radii of all atoms are similar, Cd atoms are located more inside the structure. For alkali metals, neutral and cationic endohedral compounds have been characterized and, for halogens, neutral and anionic nanoclusters have been characterized. It is observed that some of these guest atoms are trapped in the center of mass of the cluster, while others are found to be displaced from that center leading to structures where the guest atom presents a complex dynamical behavior. This fact was confirmed by quantum molecular dynamics calculations, which further confirmed the thermal stability of these endohedral compounds.