中国物理B ›› 2008, Vol. 17 ›› Issue (6): 2110-2115.doi: 10.1088/1674-1056/17/6/028

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Density functional study on structural and electronic properties of bimetallic gold--yttrium clusters: comparison with pure gold and yttrium clusters

毛华平1, 王红艳2, 盛勇3   

  1. (1)Department of Chemistry and Environment Engineering, Chongqing Three-Gorge College, Chongqing 404000, China;Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (2)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;Department of Chemistry and Center for Computational Chemistry, University of Georgia, Athens Georgia 30602, USA; (3)Material Science and Engineering College, Sichuan University, Chengdu 610065, China
  • 收稿日期:2007-09-01 修回日期:2007-11-14 出版日期:2008-06-20 发布日期:2008-06-20
  • 基金资助:
    Project supported by the Education Committee of Chongqing (Grant No KJ051105) and the National Natural Science Foundation of China (Grant No 10276028).

Density functional study on structural and electronic properties of bimetallic gold--yttrium clusters: comparison with pure gold and yttrium clusters

Mao Hua-Ping(毛华平)a)b), Wang Hong-Yan(王红艳)b)c), and Sheng Yong(盛勇)d)†   

  1. a Department of Chemistry and Environment Engineering, Chongqing Three-Gorge College, Chongqing 404000, China; b Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; c Department of Chemistry and Center for Computational Chemistry, University of Georgia, Athens Georgia 30602, USA; d Material Science and Engineering College, Sichuan University, Chengdu 610065, China
  • Received:2007-09-01 Revised:2007-11-14 Online:2008-06-20 Published:2008-06-20
  • Supported by:
    Project supported by the Education Committee of Chongqing (Grant No KJ051105) and the National Natural Science Foundation of China (Grant No 10276028).

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摘要： Employing first-principles methods, based on the density functional theory, this paper investigates the ground state geometric and electronic properties of pure gold clusters, pure yttrium clusters and gold clusters doped each with one yttrium atom. It is shown that the average bond lengths in the Au$_{n - 1}$Y($n \le $9) bimetallic clusters are shorter than those in the corresponding pure gold and yttrium clusters. The most stable isomers of the yttrium-doped gold clusters tend to equally delocalize valence s, p and d electrons of the constituent atoms over the entire structure. The Y atom has maximum number of neighbouring Au atom, which tends to be energetically favourable in the lowest-energy equilibrium structures, because the Au--Y bond is stronger than the Au-Au bond. The three-dimensional isomers of Au$_{n - 1}$Y structures are found in an early appearance starting at $n$=5 (Au$_{4}$Y). Calculated vertical ionization potential and electron affinities as a function of the cluster size show odd-even oscillatory behaviour, and resemble pure gold clusters. However, one of the most striking feature of pure yttrium clusters is the absence of odd-even alternation, in agreement with mass spectrometric observations. The HOMO--LUMO gap of Au$_{3}$Y is the biggest in all the doped Au$_{n - 1}$Y($n \le $9) bimetallic clusters.

关键词: gold--yttrium bimetallic cluster, density functional theory, HOMO--LUMO gap, equilibrium structure

Abstract: Employing first-principles methods, based on the density functional theory, this paper investigates the ground state geometric and electronic properties of pure gold clusters, pure yttrium clusters and gold clusters doped each with one yttrium atom. It is shown that the average bond lengths in the Au$_{n - 1}$Y($n \le $9) bimetallic clusters are shorter than those in the corresponding pure gold and yttrium clusters. The most stable isomers of the yttrium-doped gold clusters tend to equally delocalize valence s, p and d electrons of the constituent atoms over the entire structure. The Y atom has maximum number of neighbouring Au atom, which tends to be energetically favourable in the lowest-energy equilibrium structures, because the Au--Y bond is stronger than the Au-Au bond. The three-dimensional isomers of Au$_{n - 1}$Y structures are found in an early appearance starting at $n$=5 (Au$_{4}$Y). Calculated vertical ionization potential and electron affinities as a function of the cluster size show odd-even oscillatory behaviour, and resemble pure gold clusters. However, one of the most striking feature of pure yttrium clusters is the absence of odd-even alternation, in agreement with mass spectrometric observations. The HOMO--LUMO gap of Au$_{3}$Y is the biggest in all the doped Au$_{n - 1}$Y($n \le $9) bimetallic clusters.

Key words: gold--yttrium bimetallic cluster, density functional theory, HOMO--LUMO gap, equilibrium structure

中图分类号:  (Electronic and magnetic properties of clusters)

  • 36.40.Cg
33.15.Dj (Interatomic distances and angles) 33.15.Ry (Ionization potentials, electron affinities, molecular core binding energy) 36.40.Mr (Spectroscopy and geometrical structure of clusters)