A Density Functional Investigation of Fluorinated Silicon Clusters

Density functional calculations have been carried out on a series of fluorinated empty cages X_nF_n(n=2–20) with X?Si, Ge, and Sn. It indicates that the fullerene‐like cage structure with pentagons turns out to be the most stable with n increasing, and the stability of the X_nF_n isomers increases with the number of five‐membered rings. The HOMO‐LUMO gap for Ge (n=6, 10) cages is found to be even larger than the values for Si cages, though in bulk Ge has a smaller band gap than Si. Moreover, calculation of the Gibbs free energy of oligomerization reaction of SiF→1/n (SiF)_n showed that this reaction is exothermic even at 900 K, indicating the favorability of their formation from the SiF monomer.