A Density Functional Study of the Gold Cages MAu₁₆ (M = Si, Ge, and Sn)

Relativistic density functional calculations are performed to explore the promise of MAu₁₆(M=Si, Ge, and Sn) clusters as magic clusters and building blocks in developing cluster-assembled materials. C₁ and C_s, two isomers of SiAu₁₆, GeAu₁₆ and SnAu₁₆ with M (Ge or Sn) at the center of the cage, named, respectively, as SiAu₁₆–C₁, SiAu₁₆–C_s, GeAu₁₆-center, and SnAu₁₆-center, are calculated to be the most stable. The Au–M bond should have both ionic and covalent characteristics. Their static linear polarizabilities and first-order hyperpolarizabilities are found to be sensitive to the delocalization of the valence electrons of the M atom, as well as their structures and shapes.