Effects of Silver Doping on the Geometric and Electronic Structure and Optical Absorption Spectra of the Au25鈥?i>nAgn(SH)18鈥?/sup> (n = 1, 2, 4,

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• 作者：Emilie B. Guidez ; Ville M盲kinen ; Hannu H盲kkinen ; Christine M. Aikens
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：September 27, 2012
• 年：2012
• 卷：116
• 期：38
• 页码：20617-20624
• 全文大小：382K
• 年卷期：v.116,no.38(September 27, 2012)
• ISSN：1932-7455

文摘

The effect of silver doping of the Au₂₅(SH)₁₈^{鈥?/sup> nanoparticle is studied by investigating Au_25鈥?i>nAg_n(SH)₁₈鈥?/sup> (n = 1, 2, 4, 6, 8, 10, 12) systems using DFT. For n = 1, doping of the icosahedral shell of the metal core is energetically more favorable than doping of the metal鈥搕hiolate units or the center of the core. For n 鈮?2, only doping of the core surface is considered, and arrangements where the silver dopants are in close proximity tend to be slightly less favorable. However, energy differences are small, and all conformations are accessible under experimental conditions. Boltzmann-averaged excitation spectra for these systems show similar features to the undoped Au₂₅(SH)₁₈鈥?/sup>. The main differences include a blue shift of the low-energy HOMO鈥揕UMO (1P鈫?D) peak and an increased intensity of the peak at 2.5 eV as the number of doping silver atoms increases. Silver doping lowers the energy of ligand-based orbitals and facilitates the transitions between the superatom orbitals. Silver-doped systems show broader excitation spectra due to a breaking of the symmetry of the superatom orbitals.}