Comparative research of configuration, stability and electronic properties of cationic and neutral [AuGen]λ and [Gen+1]λ (n=1-13, λ=0, +1) nanoalloy clusters

Abstract

The configuration, stability, evolution, and electronic properties of neutral and cationic [AuGen]λ and [Gen+1]λ (n=1−13, λ=0, +1) nanoalloy clusters have been systematically investigated by using unbiased global search technique married with double-density functional strategy. The results reveal that although the neutral and cationic global minimal structures of gold-doped germanium clusters differ from each other when n=4, and 6–13, the evolution patterns are consistent. Attaching structures have been changed to Au-encapsulated motif at the turning point of n=11. The analyses of electronic structure and binding energy indicate that doping of an Au atom may decrease the stability of neutral Ge nanoclusters, but can enhance the stability of cationic Ge nanoclusters. The analyses of electronic property show that ionization potentials (IP) of Gen+1 cluster are larger than those of AuGen nanoalloy clusters, indicating that doping of an Au atom can decrease the ionization potential of neutral Ge nanoclusters. The analyses of HOMO and LUMO energy reveal that HOMO-LUMO gaps of neutral AuGen (n=1−13) with the exception of n=2 and 3 are smaller than that of Gen+1 clusters. For cations, the HOMO-LUMO gaps of [AuGen]+ are wider than that of [Gen+1]+ cluster when n=2, 5–7, and 9–11, narrower when n=3, 4, 8 and 13, and nearly identical when n=1 and 12. The PBE-DFT based global descriptors viz. Electronegativity, Hardness, Softness and Electrophilicity Index of [Gen+1]λ and [AuGen]λ (λ=0, +1; n=1−13) nanoclusters are estimated by means of HOMO-LUMO gap. And they possess highly correlation with HOMO-LUMO gap. The agreement between theoretical and experimental results such as IP, binding energy, HOMO-LUMO gap, and bond distance demonstrate the success of the computational analyses in this work.