本文選題：Gupta勢　切入點：分子動力學　出處：《原子與分子物理學報》2017年04期 　論文類型：期刊論文

【摘要】：采用恒溫分子動力學方法系統模擬研究了不同尺寸不同組分的Ag-Cu雙金屬團簇的退火過程.分析低溫退火結構可得團簇中Ag原子的偏析行為:在Ag原子所占比率較少時,Ag原子全部占據在團簇表面;隨著Ag原子數的增多,直到Ag和Cu的比率接近時,絕大多數Ag原子仍占據在團簇表面;這與實驗觀測Ag-Cu混合團簇中Ag原子的偏析行為完全一致.通過細致研究Ag-Cu雙金屬團簇中Ag原子的偏析行為與團簇尺寸、組分和溫度的關系發(fā)現:當Ag原子所占比重明顯少于Cu原子時,在各不同尺寸下,Ag原子偏析溫度點均高于熔點,即在熔點以上一定溫度范圍內仍會出現Ag原子的偏析現象;當Ag原子所占比重明顯多于Cu原子時,在各不同尺寸下,體系偏析溫度點均低于團簇熔點;對于較大尺寸團簇,在Ag原子所占比重接近于Cu原子時,體系偏析溫度點與團簇熔點相同.
[Abstract]:The system of constant temperature molecular dynamics simulation of the annealing process of Ag-Cu with different sizes and different components of bimetallic clusters. Analysis of low temperature annealing structure and segregation behavior of Ag atoms in the clusters: the proportion of less in the Ag atom, Ag atom on the surface of all clusters; with the increase in the number of Ag atoms. The ratio of Ag and Cu until the close, most of the Ag atoms still occupy in the cluster surface; the segregation behavior and experimental observation of Ag-Cu mixed clusters of Ag atoms in the same way. Through detailed research and cluster size segregation of Ag-Cu bimetallic clusters of Ag atoms, found that the relationship between composition and temperature. When the proportion of Ag atoms accounted for less than Cu atoms, in different sizes, Ag segregation temperature point higher than the melting point, the segregation phenomenon in a certain range of temperature above the melting point will appear Ag atoms; when the proportion of Ag accounted for the atom When the Cu atoms are significantly more than the Ag atoms, the segregation temperature points of the system are lower than the cluster melting points under different sizes. For larger size clusters, when the proportion of the Cu atoms is close to that of the Cu atoms, the segregation temperature of the system is the same as that of the clusters.

【作者單位】： 新疆大學物理科學與技術學院;
【基金】：國家自然科學基金(11164029)
【分類號】：O562
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本文編號：1597018