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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/7578


    Title: 以第一原理研究一到二顆金原子在θ型氧化鋁(001)表面上的吸附與擴散行為;Adsorption and diffusion of Au1~2 atoms on θ-Al2O3(001) surface : a first principle study
    Authors: 張鉑瑋;Bo-Wei Chang
    Contributors: 物理研究所
    Keywords: 第一原理;密度泛函理論;氧化鋁;金奈米粒子;first principle;DFT;θ-Al2O3;Au nano-clusters
    Date: 2009-02-27
    Issue Date: 2009-09-22 11:00:16 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 我們使用第一原理方法計算一到二顆金原子在θ型氧化鋁(001)表面上的吸附與漂移行為。首先推測了塊材氧化鋁的一截面作為吸附表面後,在所有可能吸附位置上放置第一顆金原子並投入計算,觀察結果單一顆金原子的吸附能皆低於室溫穩定吸附標準,且在表面移動所需克服的位障亦小,使得它降落表面後能迅速朝各方向漂移,且短時間內沒遇到更好的吸附狀況,則會於表面脫附。接著放置第二顆金原子在已吸附的第一顆金原子的周圍,以及直接將兩顆金原子放置在表面的對稱處用來當作金分子的漂移中間態,計算觀察結果為金分子對表面的吸附能好於單一金原子,且喜歡以立起來的方式與表面上的一顆氧鍵結,而在表面的漂移方式則喜以立起來後直接平移移動,以立起來、躺下、立起來這種滾動方式漂移的機會較少。 We have studied the adsorption and diffusion of Au1~2 atoms on θ-Al2O3(001) surface with density-functional-theory calculations. The results show that the adsorption energy (0.17-0.35 eV) and the diffusion barrier (smaller than 0.1 eV) of a single Au atom on the oxide are small. The adsorbed Au atom is expected to diffuse with no substantial energy barriers and substantial preference in any specific direction at room temperature. For dimer Au2 on the oxide surface, the calculations indicate that the dimer is thermally more stable than monomer, with an oxide-Au bonding energy 0.78 eV, and favors a geometry that one Au atom bonds with an O of the oxide surface and the other dangles. The dimer Au2 prefers to diffuse on the oxide in stand-up way more than in rolling way.
    Appears in Collections:[物理研究所] 博碩士論文

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