M₄@Si₂₈ (M=Al,Ga) Metal-encapsulated tetrahedral silicon fullerene

Authors

• Yi Gao, University of Nebraska-LincolnFollow
• Xiao Cheng Zeng, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

12-1-2005

Comments

Published by American Institute of Physics. J. Chem. Physics 123, 204325 2005. ©2005 American Institute of Physics. Permission to use. http://jcp.aip.org/.

Abstract

It is known that silicon fullerenes cannot maintain perfect cage structures like carbon fullerenes. Previous density-functional theory calculations have shown that even with encapsulated species, nearly all endohedral silicon fullerenes exhibit highly puckered cage structures in comparison with their carbon counterparts. In this work, we present theoretical evidences that the tetrahedral fullerene cage Si₂₈ can be fully stabilized by encapsulating a tetrahedral metallic cluster (Al₄ or Ga₄). To our knowledge, this is the first predicted endohedral silicon fullerene that can retain perfectly the same cage structure (without puckering) as the carbon fullerene counterpart (T_d^-C₂₈ fullerene). Density-functional theory calculations also suggest that the two endohedral metallosilicon fullerenes T_d^-M₄@Si₂₈ (M=Al,Ga) can be chemically stable because both clusters have a large highest occupied molecular orbital-lowest unoccupied molecular orbital energy gap (~0.9 eV), strong spherical aromaticity (nucleus-independent chemical shift value of −36 and −44), and large binding and embedding energies.