Structure and Stability of Zn, Cd, and Hg Atom Doped Golden Fullerene (Au₃₂)

Abstract

Structures and properties of various complexes formed between the “golden fullerene”, Au₃₂, and group IIB atoms such as Zn, Cd, and Hg have been investigated using density functional theory (DFT). Binding energy values indicate that the group IIB atoms can form stable clusters in most of the different isomeric forms of the Au₃₂ cage. The HOMO–LUMO gap of the Au₃₂ cage remains almost the same even after doping of Zn, Cd, and Hg atoms for high symmetry clusters, while it decreases for the low symmetry isomers. The highest stable isomer for the Hg-doped Au₃₂ cluster is found to be associated with <i>I</i>_<i>h</i> symmetry with a large energy difference from the other low symmetry isomers, using generalized gradient approximation (GGA) type functionals. However, for the Zn and Cd encapsulated Au₃₂ clusters, the highest stable structures are of <i>C_s</i>[1] and <i>C</i>_5<i>v</i> symmetry, respectively, along with one low symmetry isomer for each of them, having energy very close to the respective most stable isomer. Nevertheless, depending on the energy density functional, the relative energy orderings for the various isomers are found to be modified strongly. In fact, the meta-GGA TPSS functional predicts low symmetry compact isomers to be more stable for all the metal atom doped Au₃₂ clusters. Moreover, low symmetry compact isomers are found to be more stable with the dispersion-corrected GGA type PBE functional for the Zn- and Cd-doped cluster, in agreement with the TPSS results; however, the same dispersion correction fails to reproduce the TPSS results for the Hg-doped Au₃₂ system. Structural data, energetic parameters, and spectral analysis point toward the possible experimental observation of group IIB atom doped golden fullerene, which in turn might help to understand the nature of interactions between the metal atom and the Au₃₂ cage. Furthermore, experimental investigations would likely confirm the predictive ability of the different functionals used in this work