DFT Study of Small Gold Clusters Aun (n=2-13): The Structural, Electronic, Thermodynamic and Spectral Properties

Abstract

The structures and relative stabilities of small gold clusters Au_n (n=2-13) have been investigated at

The B3LYP/ CEP-121G level of density functional theory with exploitation Gaussian09 program. Relative stabilities of these clusters have been analyzed based on the variation of their binding energies (E_b), fragmentation energies (E_frag), ionization energies (VIP), electron affinities (EA), the energy gap (E_gap) and IR spectrum with cluster size (n). We note that the gold clusters Au_n (n=2, 4, 6, 8, 10, 12) have a special values of E_gap, VIP and E_frag, these indicates that these clusters are more stable than their neighbouring clusters. Binding Enthalpy (ΔH_b), Entropy (ΔS_b) and Gibbs free energy (ΔG_b) of Au_n clusters were computed at 298.15K.We note that these amounts decrease with increasing cluster size. We calculate IR spectra for gold clusters and compared our results with experimental data and we note that the clusters Au_n (n=6, 8, 10, 12) absorbed at lower wave length.

Keywords: Gold clusters, Density Functional theory (DFT), Bending energy, Fragmentation energy, Ionization energy, Electron affinity, Energy gap, Enthalpy, Entropy, Gibbs free energy, IR spectrum.