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1.
X. J. Kuang X. Q. Wang G. B. Liu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(1):71-80
An all-electron scalar relativistic calculation on
Au
n
NO (n = 1–10) clusters has been performed by using density functional
theory with the generalized gradient approximation at the PW91 level. The
small gold cluster would like to bond with nitric and the nitric monoxide
molecule prefers to occupy the on-top and single fold coordination site. The
Au
n
structures in all Au
n
NO clusters are only distorted slightly
and still keep the planar structures. With the bend of Au-N-O bond, the
structures of Au
n
NO clusters evolve from the 2D structure to 3D
structure. The most favorable adsorption between small gold cluster and
nitric monoxide molecule takes place in the case that nitric monoxide
molecule is adsorbed onto an odd-numbered pure Au
n
cluster and becomes
odd-numbered Au
n
NO cluster with even number of valence electrons. The
scalar relativistic effect strengthens the Au–Au, Au–N interaction and
weakens the N–O interaction, appearing as the shorter Au–Au, Au–N
bond-length and the longer N–O bond-length. The differences between our work
and previous work are believed to be the reflection of the scalar
relativistic effect. 相似文献
2.
X. J. Kuang X. Q. Wang G. B. Liu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,63(1):111-122
An all-electron scalar relativistic calculation on
Au
n
Pt (n = 1−12) clusters has been
performed by using density functional theory with the generalized gradient approximation
at PW91 level. Our results reveal that all the lowest energy geometries of
Au
n
Pt (n = 1−12) clusters may be
generated by substituting Pt atom for one gold atom of the
Au
n+1 cluster at the highest coordinated site. Compared with
corresponding pure Au
n+1 cluster, the lowest energy geometries
of Au
n
Pt clusters are distorted slightly and still keep the
planar structures due to the strong scalar relativistic effect in small gold cluster. The
Au-Pt bonds are stronger and most Au-Au bonds far from Pt atom are weaker than the
corresponding Au-Au bonds in pure Au
n+1 cluster. By
substituting Pt atom for one gold atom of Au
n+1 cluster at the
highest coordinated site, the relatively stable and inactive odd-numbered
Au
n+1 cluster becomes the relatively unstable and reactive
odd-numbered Au
n
Pt cluster, and the relatively unstable and
reactive even-numbered Au
n+1 cluster becomes the relatively
stable and inactive even-numbered Au
n
Pt cluster chemically
and electronically. All the Au
n
Pt clusters prefer low spin
multiplicity. The even-numbered Au
n
Pt clusters are found to
exhibit zero magnetic moment and the odd-numbered
Au
n
Pt clusters are found to possess magnetic moment with the
value of 1 μ
B. The odd-even alterations of magnetic moments
and electronic configurations for Au
n
Pt clusters are very
obvious and may be simply understood in terms of the electron pairing effect. 相似文献
3.
A systematic study on the geometrical structures, electronic and magnetic properties of Au5H
n
(n=1–10) clusters has been performed by using the all-electron scalar relativistic density functional theory with generalized
gradient approximation at the PW91 level. It is found that all Au5H
n
clusters prefer to keep the planar structures like pure Au5 cluster, the Au5 structures in Au5H4, Au5H5 and Au5H6 clusters are distorted obviously. The adsorption of a number of hydrogen atoms enhances the stability of Au5 cluster and all Au5H
n
clusters are more stable than pure Au5 cluster energetically. The odd-even alteration of magnetic moment is observed in Au5H
n
clusters and may be served as the material with tunable code capacity of “0” and “1” by adsorbing odd or even number of H
atoms. It seems that the most favorable adsorption between Au5 cluster and a number of hydrogen atoms takes place in the case that the odd number of hydrogen atoms is adsorbed onto Au5 cluster and becomes Au5H
n
cluster with even number of valence electrons. 相似文献
4.
M. Vogel K. Hansen A. Herlert L. Schweikhard 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):73-76
The decay pathway competition between monomer and dimer evaporation of photoexcited cluster ions Au
+
n, n = 2-27, has been investigated by photodissociation of size-selected gold clusters stored in a Penning trap. For n > 6 the two decay pathways are distinguished by their experimental signature in time-resolved measurements of the dissociation.
For the smaller clusters, simple fragment spectra were used. As in the case of the other copper-group elements, even-numbered
gold cluster ions decay exclusively by monomer evaporation, irrespective of their size. For small odd-size gold clusters,
dimer evaporation is a competitive alternative, and the smaller the odd-sized clusters, the more likely they decay by dimer
evaporation. In this respect, Au
+
9 shows an anomalous behavior, as it is less likely to evaporate dimers than its two odd-numbered neighbors, Au
+
7 and Au
+
11. This nonamer anomaly is typical for copper-group cluster ions M
+
9 (M = Cu, Ag, Au) and a similar behavior is found in the anionic heptamers M
-
7. It is discussed in terms of the well-known electronic shell closing at n
e = 8 atomic valence electrons.
Received 2 November 2000 相似文献
5.
6.
Geometrical,energetic and electronic properties of Au_n-(C_3H_6O)_m complexes(n = 3,5,m≤n):A density functional theory study 下载免费PDF全文
<正>The interactions of acetone molecules with clusters of AU_3 and Au_5 are investigated by using a density functional theory(DFT) within a generalized gradient approximation(GGA).The geometries,adsorption energies and deformation electron density distributions are used to analyse these interactions.The present calculations show that more than one acetone molecule can be adsorbed onto small gold clusters,and this adsorption is different from that of single molecule absorption.The coordination number of the adsorption site on the gold cluster is the dominant factor responsible for the strength of the interactions.The effects of the Au-O bond lengths in the complexes on adsorption energies between Au clusters and acetone molecules are also examined. 相似文献
7.
Equilibrium geometries, relative stabilities, and magnetic properties of small AunMn (n=1-8) clusters have been investigated using density functional theory at the PW91P86 level. It is found that Mn atoms in the ground state AunMn isomers tend to occupy the most highly coordinated position and the lowest energy structure of AunMn clusters with even n is similar to that of pure Aun+1 clusters, except for n=2. The substitution of Au atom in Aun+1 cluster by a Mn atom improves the stability of the host clusters. Maximum peaks are observed for AunMn clusters at n=2, 4 on the size dependence of second-order energy differences and fragmentation energies, implying that the two clusters possess relatively higher stability. The HOMO-LUMO energy gaps of the ground state AunMn clusters show a pronounced odd-even oscillation with the number of Au atoms, and the energy gap of Au2Mn cluster is the biggest among all the clusters. The magnetism calculations indicate that the total magnetic moment of AunMn cluster, which has a very large magnetic moment in comparison to the pure Aun+1 cluster, is mainly localized on Mn atom. 相似文献
8.
Y. Dong M. Springborg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):15-18
The geometries and electronic properties of the most stable small
Aun clusters with n=2 to 20 are presented.
An intensive search for low-energy minima of Aun clusters was carried
through using a density-functional tight-binding method combined with genetic algorithms for an unbiased global structure
optimization. The structural and energetic properties of the small gold clusters are compared with those of planar Aun clusters with n=5 to 15. 相似文献
9.
I. L. Garzón M. R. Beltrán G. González I. Guterrez-González K. Michaelian J. A. Reyes-Nava J. I. Rodrguez-Hernández 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):105-109
Theoretical and experimental information on the shape and
morphology of bare and passivated gold clusters is fundamental
to predict and understand their electronic, optical, and other
physical and chemical properties. An effective theoretical
approach to determine the lowest-energy configuration (global
minimum) and the structures of low energy isomers (local minima)
of clusters is to combine genetic algorithms and many-body
potentials (to perform global structural optimizations), and
first-principles density functional theory (to confirm the
stability and energy ordering of the local minima). The main
trend emerging from structural optimizations of bare Au clusters
in the size range of 12-212 atoms indicates that many
topologically interesting low-symmetry, disordered structures
exist with energy near or below the lowest-energy ordered
isomer. For example, chiral structures have been obtained as the
lowest-energy isomers of bare Au28 and
Au55 clusters, whereas in the size-range
of 75-212 atoms, defective Marks decahedral structures are
nearly degenerate in energy with the ordered symmetrical
isomers. For methylthiol-passivated gold nanoclusters
[Au28(SCH3)16
and
Au38(SCH3)24],
density functional structural relaxations have shown that the
ligands are not only playing the role of passivating molecules,
but their effect is strong enough to distort the metal cluster
structure. In this work, a theoretical approach to characterize
and quantify chirality in clusters, based on the Hausdorff
chirality measure, is described. After calculating the index of
chirality in bare and passivated gold clusters, it is found that
the thiol monolayer induces or increases the degree of chirality
of the metallic core. We also report simulated high-resolution
transmission electron microscopy (HRTEM) images which show that
defects in decahedral gold nanoclusters, with size between 1-2
nm, can be detected using currently available experimental HRTEM
techniques. 相似文献
10.
M. Zhang S. Chen Q. M. Deng L. M. He L. N. Zhao Y. H. Luo 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,58(1):117-123
The geometries and electronic properties of the 3p electrons atoms doped gold cluster: M@Au6 clusters (M=Al, Si, P, S, Cl, Ar) have been systematically investigated by using relativistic all-electron density functional
theory (VPSR) and scalar relativistic effective core potential Stuttgart/Dresden (SDD) basis. Generalized gradient approximation
in the Perdue-Burke-Ernzerhof (PBE) functional form is chosen for geometry optimization. A number of new isomers are obtained
for neutral M@Au6 clusters. Both PBE/VPSR and PBE/SDD methods give similar lowest energy structure of each M@Au6cluster. With the exception of Ar@Au6, all doped clusters show larger relative binding energies compared with pure Au7 cluster. It is found that all the ground-state structures of the M@Au6 clusters prefer the low symmetry structures, which is very different to the 3d transition-metal impurity doped Au6 clusters. Our results are in excellent agreement with available experiment data. 相似文献
11.
B. Kalita R. C. Deka 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(1):51-58
Density functional calculations have been performed to investigate CO adsorption on neutral, cationic and anionic Pdn (n=1–7) clusters. From the results, it is observed that the binding of CO molecule to neutral and cationic palladium clusters
takes place via 1-, 2- and 3-fold coordination. On the other hand, only terminal adsorption of CO molecule is possible in
anionic clusters barring bridging adsorption in Pd7
- cluster. 相似文献
12.
Adsorption of acetylene and ethane molecules by water clusters has been investigated by the molecular dynamics method at T=233 K. With the help of determination of statistical weights the cluster systems are created. In the frequency range of 0?ω?1000 cm−1 the integral absorption coefficient of IR-radiation increases after the adsorption of acetylene or ethane molecules by the ultra disperse water system. The dissipation power of IR-radiation by cluster systems increases if C2H2 molecules are adsorbed, and it reduces in the case of C2H6 molecules' adsorption. 相似文献
13.
Geometrical, electronic, and magnetic properties of the Sc-doped gold clusters, AunSc (n=1-8), have been studied using the density-functional theory within the generalized gradient approximation. An extensive structural search shows that the Sc atom in low-energy AunSc isomers tends to occupy the most highly coordinated position. The substitution of a Sc atom for an Au atom in the Aun+1 cluster markedly changes the structure of the host cluster. Moreover, we confirm that the ground-state Au6Sc cluster has a distortion to a lower D2h symmetry. The relative stabilities and electronic properties of the lowest-energy AunSc clusters are analyzed based on the averaged binding energies, second-order energy differences, fragmentation energies, chemical hardnesses, and HOMO-LUMO gaps. It is found that the magic Au3Sc cluster can be perceived as a superatom with high chemical stability and its HOMO-LUMO gap is larger than that of the closed-shell Zr@Au14 cluster. The high symmetry and spin multiplicity of the Au3Sc and Au6Sc clusters are responsible for their large vertical ionization potential and electron affinity. The magnetism calculations indicate that the magnetic moment of the Sc atom in the ground-state AunSc (n=2-8) clusters gradually decreases for even n and is completely quenched for odd n. 相似文献
14.
All-electron scalar relativistic calculations on Au5X (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) clusters have been performed by using density functional theory with the
generalized gradient approximation. Our calculation results indicate that all the lowest energy geometries of Au5X clusters have planar structures; the doped X atoms prefer to occupy the fourfold coordination site. Except Au5Fe, Au5Co and Au5Zn, for other clusters including pure Au6 cluster, the HOMO are delocalized obviously with a contribution from all atoms in the cluster. On the contrary, the electron
localization in Au5Zn is very strong resulting in the least stability of this cluster. Au5Cu cluster with six delocalized electrons being defined as magic number for two-dimensional system has the largest VIP and
deepest HOMO energy level. With the substitution Au for X atoms, the metallicity of all Au5X clusters is reinforced. 相似文献
15.
Polycrystalline Ag, Ag20Au80, Ag40Au60, Ag80Au20 and Au samples were bombarded with 15 keV Ar+ at 60° incidence and the resulting secondary neutral yield distribution was studied by non-resonant laser postionisation mass spectrometry. Neutral clusters containing up to 21 atoms were observed for the targets. The yield of neutral clusters, AgmAun−m, containing n atoms, Yn, was found to follow a power in n, i.e. Yn ∝ n−δ, where the exponent δ varied from 3.2 to 4.0. For a fixed n, the cluster yields showed a variation with number of gold atoms similar to that expected for a binomial distribution. In addition, the cluster compositions from the sputtered alloys were indicative of sputtering from a gold rich surface. 相似文献
16.
Shuang Zhao GuoZhi Li JunNa Liu YunLai Ren WeiWei Lu JianJi Wang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2014,68(9):1-8
Density functional theory calculations were performed to investigate the structural and energetic properties of chemisorbed Au n -(C2H4) x and Pd n -(C2H4) x complexes, with n = 2 ? 4 and x = 1 ? 4. Adsorption in π-bonded mode dominates in Au n -(C2H4) x species irrespective of x while the di-σ mode can be formed in the most stable Pd n -(C2H4) x species. The adsorption energy decreases as the number of C2H4 molecules increases in Au n -(C2H4) x with n ? 4 and Pd n -(C2H4) x with n ? 3. The adsorption of one C2H4 molecule on bimetallic Au/Pd clusters has also been studied. The C2H4 molecule prefers binding to Pd atoms in π-bonded configuration on Au/Pd clusters. The net charge transfer and the typical shift in the vibrational frequencies of C2H4 have also been determined and discussed. 相似文献
17.
Alexander A. Rusakov Yuriy A. Demidov Andréi Zaitsevskii 《Central European Journal of Physics》2013,11(11):1537-1540
We report first-principle based studies of element 113 (E113) interactions with gold aimed primarily at estimating the adsorption energy in thermochromatographic experiments. The electronic structure of E113-Au n systems was treated within the accurate shape-consistent small core relativistic pseudopotential framework at the level of non-collinear relativistic density functional theory (RDFT) with specially optimised Gaussian basis sets. We used gold clusters with up to 58 atoms to simulate the adsorption site on the stable Au(111) surface. Stabilization of the E113-Au n binding energy and the net Bader charge of E113 and the neighboring Au atoms with respect to n indicated the cluster size used was appropriate. The resulting adsorption energy estimates lie within the 1.0–1.2 eV range, substantially lower than previously reported values. 相似文献
18.
The density functional method with the relativistic effective core potential has been employed to investigate systematically the geometric structures, relative stabilities, growth-pattern behavior, and electronic properties of small bimetallic Au n Rb (n?=?1–10) and pure gold Au n (n?≤?11) clusters. For the geometric structures of the Au n Rb (n?=?1–10) clusters, the dominant growth pattern is for a Rb-substituted Au n +1 cluster or one Au atom capped on a Au n –1Rb cluster, and the turnover point from a two-dimensional to a three-dimensional structure occurs at n?=?4. Moreover, the stability of the ground-state structures of these clusters has been examined via an analysis of the average atomic binding energies, fragmentation energies, and the second-order difference of energies as a function of cluster size. The results exhibit a pronounced even–odd alternation phenomenon. The same pronounced even–odd alternations are found for the HOMO–LUMO gap, VIPs, VEAs, and the chemical hardness. In addition, about one electron charge transfers from the Au n host to the Rb atom in each corresponding Au n Rb cluster. 相似文献
19.
Norimichi Kojima Yasuhiro Kobayashi Yuichi Negishi Makoto Seto Tatsuya Tsukuda 《Hyperfine Interactions》2013,217(1-3):91-98
197Au Mössbauer spectra of a series of glutathionate-protected gold clusters, Au n (SG) m , with n = 10 ? ~55, were re-analyzed to understand the structure evolution behavior. The numbers of gold atoms coordinated by different numbers (0, 1, and 2) of the GS ligands were successfully determined by assuming individual isomer shifts and quadrupole splittings for the three sites in Au25(SG)18 (Tsukuda et al., Chem Lett 40:1292, 2011). The analysis revealed the drastic structural evolution of Au n (SG) m in the range of n = 10 ? ~55. In Au10(SG)10, all the gold atoms are bonded to GS ligands, indicating –Au–S(G)– cyclic structures. A catenane structure was proposed for Au10(SG)10. At n = 25, a single Au atom without the GS ligation appeared, consistent with the formation of an icosahedral Au13 core protected by six staples, –S(G)–[Au–S(G)–]2. At n = 39, it is considered that Au39(SG)24 has a similar structure to that of Au38(SC2H4Ph)24 with face-fused bi-icosahedral Au23 core. 相似文献
20.
给出了优化小分子在团簇表面吸附结构的遗传算法.结合经验势函数,搜寻了水分子在(TiO2)n(n=3—6)团簇上可能的吸附方式;利用B3LYP/6-31G**方法对各种吸附结构进行了优化.结果表明水分子主要通过O原子以非解离方式吸附到团簇中配位数较低或位置比较凸出的Ti原子上.分子轨道分析表明,水分子与团簇之间的成键主要来自吸附位Ti原子3s3p轨道的贡献,水分子的轨道保持了气相水分子中的基本特征,但离域化程度增大
关键词:
2团簇')" href="#">TiO2团簇
2O吸附')" href="#">H2O吸附
遗传算法
DFT 相似文献