Static polarizabilities and optical absorption spectra of gold clusters (Aun,n=2–14and 20) from first principles

Abstract

Static polarizabilities and optical absorption spectra for the ground state structures of gold clusters ͑Au n , n =2-14 and 20͒ are investigated from first principles within static and time-dependent density functional theory. The static polarizabilities of clusters with less than 14 atoms generally increase as a function of size modulated by even-odd oscillations. The polarizabilities of Au 14 and Au 20 are noticeably lower due to the shape transition from two-dimensional to three-dimensional structures at n = 14. The analyses of the optical absorption spectra calculated within the time-dependent local density approximation indicate that the d electrons in Au n clusters are significantly more involved in low-energy transitions and give rise to more quenched oscillator strengths ͑by screening the s electrons͒ than in Ag n clusters. These stronger effects of the d electrons in the optical properties of Au n are due to the larger degree of proximity of the s and d levels in the Au atom as compared to the Ag atom, which gives rise to stronger s-͑p͒-d hybridization in the molecular orbitals of Au n . The calculated spectra are found to be in good agreement with experimental data and results from earlier studies for the available sizes.

First-Principles Investigation of Ag-Doped Gold Nanoclusters

“…Regarding Au 20 in Figure.3, there are two main peaks in ɛ 2 ( ω ), at 1.79 and 2.51 eV, respectively (namely E 1 , E 2 ), which are very close to the previous results of 1.86 and 2.78 [21]. It can be seen in the inset of Figure 3 that direct transition can be caused between HOMO and LUMO.…”

“…It can be seen in the inset of Figure 3 that direct transition can be caused between HOMO and LUMO. Therefore, it can be expected that E 1 (1.79 eV) should mainly be caused by optical transitions between Au 6 s 55% (and Au d , 45% ) states in HOMO and Au 6 s states in LUMO, which are close to the other first-principles evaluation (1.86 eV) [21]. Moreover, it is not far from the HOMO-LUMO gap of 1.48 eV.…”

“…These models of gold clusters refer to the previous work, which has shown that the best structural stability and average distance between Au-Au bonding is about 2.73 Å [21]. The substitutional method has been taken into account in this paper, and Ag atoms are used to substitute Au atoms in vertex site.…”

Promote water photosplitting via tuning quantum well states in supported metal clusters

“…It agrees with previous studies, where Au 8 has been found to be more stable than Au 7 (by 0.12 eV/Au) and Au 9 (by 0.03 eV/Au). 30 In addition, it has also been found that small 2D structures (n 9) are more favorable than corresponding 3D structures in vacuum. 30,31 We then investigate the structure and properties of supported small gold clusters adsorbed on MgO/Ag(001).…”

“…30 In addition, it has also been found that small 2D structures (n 9) are more favorable than corresponding 3D structures in vacuum. 30,31 We then investigate the structure and properties of supported small gold clusters adsorbed on MgO/Ag(001). The optimized atomic configuration of the Au 8 cluster on 2 ML MgO/Ag(001) is shown in Fig.…”