| During recent years, an amount of previous experimental and theoreticalstudiesrevealed unique catalytic, electronic, and optical properties of gold clusters aswell as their novel applications in domains of nanomaterials and catalysts. Recently,massive investigations indicated that the bimetallic system have better catalyticeffectiveness than the pure metal system, because impurity atoms may obviouslychange the geometric, electronic and bonding properties of host clusters. In particular,transition metal-doped gold clusters have been becoming a growing interest becausetransition metal elements possess intricate d-orbital bonding, strong electron correlation,and spin-orbit coupling which strongly influence the chemical and physical propertiesof host gold clusters.In this paper under the framework of density functional theory, we have performeda first principles all-electron scalar relativistic calculation on the geometrical structures,properties stabilityof gold-based binary alloy clusters (AunRe, AunCd and AunHg). Themain results are summarized below:For AunRe (n=1–12) clusters,based on the density functional theory with usingrelativistic all electron methods, we systematically study the geometrical structures,relative stabilities, electronic properties, and chemical hardness of AunRe (n=1–12)clusters.Low-lying energy structures include two-dimensional and three-dimensionalgeometries. Especially, for the lowest energy structures of AunRe (n=112) clusters,the planar to three dimensional transformation is found to occur at cluster size n=10andthe dopant Re atom prefers being located at highly coordinated site.After doping a Reatom, the relatively stable odd-numbered Aun+1cluster becomes the relatively unstableodd-numbered AunRe cluster, while the relatively unstable even-numbered Aun+1clusterbecomes the relatively stable even-numbered AunRe cluster. Moreover,the presence ofdopant Re atom leads to the chemical reactivity of even-numbered gold clustersbecomes weaker, but the chemical reactivity of odd-numbered gold clusters turnsstronger.For AunCd (n=1–12) clusters, we systematically study the geometrical structures,relative stabilities, electronic properties, and chemical hardness of AunCd (n=1–12)clusters based on the framework of the density functional theory with using relativisticall electron methods. Low-lying energy structures include two-dimensional and three-dimensional geometries. Especially, all the lowest energy structures of AunCd (n=112) clusters are inclined to be planar geometries with slight distortion, in which thedopant Cd atom has higher coordination at n=2-6, but lower coordination at n=7-12.The fragmentation energies, second-order difference of energies, the highestoccupied-lowest unoccupied molecular orbital gaps and chemical hardness ofAunCd andAun+1exhibit a pronounced even-odd alternations phenomenon in reverse order. Thisresult indicates that the geometrical, electronic and chemical stabilities of AunCdwitheven number of valence electrons are higher than those of neighboring AunCdwith oddnumber of valence electrons and corresponding Aun+1with odd number of valenceelectrons. Additionally,Au-Cd bonds of AunCd clusters are weaker and have moreobviously ionic-like characteristics than corresponding Au-Au bonds of Aun+1.For AunHg (n=1–12), the geometrical structures, relative stabilities, electronicproperties and chemical hardness of AunHg (n=1–12) clusters are systematicallyinvestigated using the density functional theory with relativistic all electron methods.The optimized low-lying energy geometries exhibittwo-dimensional andthree-dimensional structures. Furthermore, all the lowest energy structures of AunHg (n=112) clusters favor planar geometries with slight distortion, in which the dopant Hgatom prefers to occupy a peripheral site with a lower coordination. The fragmentationenergies, second-order difference of energies, the highest occupied-lowest unoccupiedmolecular orbital gaps and chemical hardness ofAunHg and Aun+1show remarkableodd-even oscillatory behaviors in reverse order. This result suggests that thegeometrical, electronic and chemical stabilities of AunHgwith even number of valenceelectrons are higher than those of neighboring AunHgwith odd number of valenceelectrons and corresponding Aun+1with even number of valence electrons.Besides,Au-Hg bonds of AunHg clusters are weaker and have more obviously ionic-likecharacteristics than correspondingAu-Au bonds of Aun+1.On the other hand, because of similar outer valent electronic shells of Re, Cd andHg atomsodd-numbered doping clusters have higher chemical reactivities and lowerrelative stabities than corresponding odd-numbered gold clusters, while even-numbereddoping clusters have lower chemical reactivities and higher relative stabities thancorresponding even-numbered gold clusters, namly the presence of dopant Re, Cd andHg atoms reverse the even-odd effects of gold clusters. Besides, by comparison withpure gold clusters, there are the stronger Re-Au interactions in AunRe clusters, whilethere are the weaker Hg-Au or Cd-Au in AunHg or AunCd clusters. This leads to doping a Re atom can generally enhance the structural stability of gold clusters, but doping aHg or Cd atom can slightly lower the structural stability of gold clusters. Furthermore,this also leads to Re atom can strongly influence the lowest-energy structure of goldclusters, and however Hg or Cd atom can just slightly change the lowest-energystructure of gold clusters and their doped cluster still keep the planar structures.In our study, we systematically investigate structures and properties of AunRe,AunCd andAunHg clusters. Especially, we focus on the stable structures, electronicproperties, chemical reactivity of doping clusters and the differences among AunRe,AunCd and AunHg clusters. Meanwhile, we obtain some novel and interesting findings.Finally, we expect that our research would be constructive to deeply understand thestructures and properties of gold-based binary nano-cluster, and guide further theoreticaland experimental studies. |
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