Density functional study on structural and electronic properties of bimetallic gold--yttrium clusters: comparison with pure gold and yttrium clusters |
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Authors: | Mao Hua-Ping Wang Hong-Yan and Sheng Yong |
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Institution: | Department of Chemistry and Environment
Engineering,
Chongqing Three-Gorge College, Chongqing 404000, China;Institute of Atomic and Molecular Physics, Sichuan
University, Chengdu 610065, China; 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; Material Science and Engineering College, Sichuan
University, Chengdu 610065, China |
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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 Augold--yttrium bimetallic cluster,
density functional theory, HOMO--LUMO gap, equilibrium structureProject supported by the Education
Committee of Chongqing (Grant No KJ051105) and the National Natural
Science Foundation of China (Grant
No 10276028).3640, 3640B, 3120A, 3130J9/1/2007 12:00:00 AMEmploying 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 Augold--yttrium bimetallic cluster,
density functional theory, HOMO--LUMO gap, equilibrium structureProject supported by the Education
Committee of Chongqing (Grant No KJ051105) and the National Natural
Science Foundation of China (Grant
No 10276028).3640, 3640B, 3120A, 3130J9/1/2007 12:00:00 AMEmploying 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. |
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Keywords: | gold--yttrium bimetallic cluster density functional theory HOMO--LUMO gap equilibrium structure |
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