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Theoretical Studies on Gold Based Binary Metal Clusters

Author: XueQingFeng
Tutor: TianWeiQuan
School: Harbin Institute of Technology
Course: Physical and chemical
Keywords: Au-binary alloys metal clusters quantum chemical calculations MP2 structure stability
CLC: O641.1
Type: Master's thesis
Year: 2012
Downloads: 17
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Abstract

Alloy is used more widely than pure metal for its excellent properties in ourlives. Au attracted a lot of chemists and physicists for its chemical and physicalproperties. People pay more and more attention to the Au alloys, and now the Aualloys were widely used in many fields, such as electronic devices, light absorption,the catalytic and biological medicine. The groundwork of studying Au, Au alloys andnano Au materials is developing theories of Au clusters, structure of Au alloys andtheir properties. So the related experimental and theoretical research has muchimportant scientific and practical values.Nowadays, the research of Au clusters is mainly focused on the structures,adsorption capacity and catalytic ability of Au alloys. The present thesis presents atheoretical basis for the synthesis, application and properties of Au alloys bysearching the stable structure and studying bonding properties of the Au clustersformed with metals across the periodic table of elements and Au. This thesis mainlycontains following contents: the first part studies the diatomic Au clusters. At first,suitable quantum chemical method and basis set for this topic were chosen. With thestable structure of the diatomic Au clusters, bond length, bond angle, bonding energy,bond order and frequency of the stable structure were studied. What’s more, thenatural bond orbital analysis was carried out. The second part is studying the ternaryAu clusters.Diatomic Au clusters of the elements in the fifth and sixth lines of periodic tableare more stable than their fourth periodic counterparts in sense of their bondingenergies, however, the Au-Cu alloy has the highest bonding energy; Zr, W and Iralloys have larger energy gap; Au-Ti and ⅧB alloys have larger bond order;however, the charge transfer of ⅧB, ⅤB and ⅦB alloys are significant and showeven-odd oscillation.The ⅤB, ⅦB and transition elements show largest bondingabilities to Au. To tri-atomic Au clusters, the ⅢB, ⅤB and ⅦB alloys in the fourthand fifth periodic table have the largest bonding energies; the energy gaps of thealloys in fourth line of periodic table are larger than the clusters formed from theelements of the other two lines in periodic table; the charge transfer of ⅢB toⅥBclusters in the fourth and fifth line of periodic table are more obviously. To Au2Xclusters, the bonding energies of ⅤB and ⅦB alloys in the fifth and sixth periodictable are bigger; the energy gaps of the ⅥB, ⅧB alloys in the fourth and fifthperiodic table are bigger; the charge transfer of ⅤB, ⅦB and ⅧB clusters in thefourth periodic table are more significant. In summary, the tri-atomic Au_mX_nclusters of ⅢB and ⅤB in the fourth periodic table are more stable.

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