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1.
The geometrical, electronic, and magnetic properties of small Au n V (n?=?1–8) clusters have been investigated using density functional theory at the PW91 level. An extensive structural search indicates that the V atom in low-energy Au n V isomers tends to occupy the most highly coordinated position and the ground-state configuration of Au n V clusters favors a planar structure. The substitution of a V atom for an Au atom in the Au n +1 cluster transforms the structure of the host cluster. Maximum peaks are observed for the ground-state Au n V clusters at n?=?2 and 4 for the size dependence of the second-order energy differences, implying that the Au2V and Au4V clusters possess relatively higher stability. The energy gap of the Au3V cluster is the largest of all the clusters. This may be ascribed to its highly symmetrical geometry and closed eight-electron shell. For ground-state clusters with the same spin multiplicity, as the clusters size increases, the vertical ionization potential decreases and the electron affinity increases. Magnetism calculations for the most stable Au n V clusters demonstrate that the V atom enhances the magnetic moment of the host clusters and carries most of the total magnetic moment. 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.
Geometries, stabilities, and electronic properties of Be-doped gold clusters: a density functional theory study
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We have systematically investigated the geometrical structures, relative stabilities and electronic properties of small bimetallic AunBe (n = 1, 2, . . . , 8) clusters using a density functional method at BP86 level. The optimized geometries reveal that the impurity beryllium atom dramatically affects the structures of the Aun clusters. The averaged binding energies, fragmentation energies, second-order difference of energies, the highest occupied-lowest unoccupied molecular orbital energy gaps and chemical hardness are investigated. All of them exhibit a pronounced odd-even alternation, manifesting that the clusters with even number of gold atoms possess relatively higher stabilities. Especially, the linear Au2Be cluster is magic cluster with the most stable chemical stability. According to the natural population analysis, it is found that charge-transferring direction between Au atom and Be atom changes at the size of n = 4. 相似文献
4.
Mao Ai-Jie Kuang Xiao-Yu Chen Gang Zhao Ya-Ru Li Yan-Fang Lu Peng 《Molecular physics》2013,111(11):1485-1494
The ab initio method based on density functional theory at the B3PW91 level has been applied to study the geometric, electronic, and magnetic properties of neutral and anionic Au n Pd (n?=?1–9) clusters. The results show that the most stable geometric structures adopt a three-dimensional structure for neutral Au7Pd and Au8Pd clusters, but for anionic clusters, no three-dimensional lowest-energy structures were obtained. The relative stabilities of neutral and anionic Au n Pd clusters were analysed by means of the dependent relationships between the binding energies per atom, the dissociation energies, the second-order difference of energies, the HOMO–LUMO energy gaps and the cluster size n, and a local odd–even alternation phenomenon was found. Natural population analysis indicates the sequential transfer from the Pd atom to the Au n frame in Au1,2,3,5Pd and Au2,3Pd? clusters, and from the Au n frame to the Pd atom in other clusters. Much to our surprise, irrespective of whether it is the total magnetic moment or the local magnetic moment, the magnetic moment presents an odd–even alternation phenomenon as a function of the cluster size n. The magnetic effects are mainly localized on the various atoms (Au or Pd) for different cluster size n. 相似文献
5.
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
6.
The geometrical structures, relative stabilities, electronic and magnetic properties of calcium-doped gold clusters Au n Ca (n?=?1–8) have been systematically investigated by employing density functional method at the BP86 level. The optimised geometries show that the ground-state structures are planar structures for Au n Ca (n?=?3–8) clusters. Ca-substituted Au n +1 clusters, as well as Au-capped Au n ?1Ca clusters, are dominant growth patterns for the Au n Ca clusters. The relative stabilities of Au n Ca clusters for the ground-state structures are analysed based on the averaged binding energies, fragmentation energies and second-order difference of energies. The calculated results reveal that the Au2Ca isomer is the most stable structure for small size Au n Ca (n?=?1–8) clusters. The HOMO-LUMO energy gaps as a function of the cluster size exhibit a pronounced even–odd alternation phenomenon. Subsequently, charge transfers and magnetic moment of Au n Ca (n?=?1–8) clusters have been analysed further. 相似文献
7.
Density-functional method PW91 has been selected to investigate the structural, electronic and magnetic properties of Au4M (M =Sc–Zn) clusters. Geometry optimisations show that the M atoms in the ground-state Au4M clusters favour the most highly coordinated position. The ground-state Au4M clusters possess a solid structure for M = Sc and Ti and a planar structure for M = V–Zn. The characteristic frequency of the doped clusters is much greater than that of pure gold cluster. The relative stability and chemical activity are analysed by means of the averaged binding energy and highest occupied molecular orbital and lowest unoccupied molecular orbital energy gap for the lowest energy Au4M clusters. It is found that the dopant atoms can enhance the thermal stability of the host cluster except for Zn atom. The Au4Ti, Au4Mn and Au4Zn clusters have relatively higher chemical stability. The vertical detachment energy, electron affinity and photoelectron spectrum are calculated and simulated theoretically for all the ground-state structures. The magnetism calculations reveal that the total magnetic moment of Au4M cluster is mainly localised on the M atom and vary from 0 to 5 μB by substituting an Au atom in Au5 cluster with different transition-metal atoms. 相似文献
8.
ABSTRACTDensity functional theory calculations have been carried out on ternary PtmAunAgl clusters of low nuclearity (m?+?n+l?=?5, 6 and 7). Various properties including average bond distance, binding energy, mixing energy, ionisation potential, electron affinity, HOMO–LUMO gap and fragmental channel, are reported for the optimised structures. The variations of the calculated properties of the PtmAunAgl clusters as a function of concentrations (i.e. all m-, n-, and l-values) are displayed by ternary diagrams. The geometric, energetic and electronic properties are sensitive to the composition and size of PtmAunAgl clusters. 相似文献
9.
Density functional theory has been applied to study the geometric structures, relative stabilities, and electronic properties of cationic [AunRb]+ and Aun + 1+ (n = 1–10) clusters. For the lowest energy structures of [AunRb]+ clusters, the planar to three-dimensional transformation is found to occur at cluster size n = 4 and the Rb atoms prefer being located at the most highly coordinated position. The trends of the averaged atomic binding energies, fragmentation energies, second-order difference of energies, and energy gaps show pronounced even–odd alternations. It indicated that the clusters containing odd number of atoms maintain greater stability than the clusters in the vicinity. In particular, the [Au6Rb]+ clusters are the most stable isomer for [AunRb]+ clusters in the region of n = 1–10. The charges in [AunRb]+ clusters transfer from the Rb atoms to Aun host. Density of states revealed that the Au-5d, Au-5p, and Rb-4p orbitals hardly participated in bonding. In addition, it is found that the most favourable channel of the [AunRb]+ clusters is Rb+ cation ejection. The electronic localisation function (ELF) analysis of the [AunRb]+ clusters shown that strong interactions are not revealed in this study. 相似文献
10.
Norimichi Kojima Kazuhiro Ikeda Yasuhiro Kobayashi Tatsuya Tsukuda Yuichi Negishi Genta Harada Tadashi Sugawara Makoto Seto 《Hyperfine Interactions》2012,207(1-3):127-131
We have investigated the structures and electronic states of a series of glutathionate-protected Au clusters, Au n (SG) m with n = 10 ? ~55, using 197Au Mössbauer spectroscopy, which allows us to probe the local environment of the constituent Au atoms via isomer shift (IS) and quadrupole splitting (QS). The spectral profile abruptly changes on going from Au22(SG)17 to Au25(SG)18, then it smoothly changes to that of Au~55(SG)m. However, the spectral profile dramatically changes on going from Au~55(SG)m to the dodecanethiolate-protected Au cluster with average diameter of 2 nm. The 197Au Mössbauer spectra of glutathionate-protected Au clusters and dodecanethiolate-protected Au clusters were successfully analyzed on the basis of the structure and electronic state of Au25(SG)18. 相似文献
11.
12.
Y. Li Y. P. Cao Y. F. Li S. P. Shi X. Y. Kuang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(1):7
The ab initio method based on density functional theory at the PW91PW91 level has been employed to systematically study the
structures, stabilities, electronic, and magnetic properties of gold clusters with or without silicon/phosphorus doping. The
optimized geometries show that the most stable isomers for Au
n
Si2 and Au
n
P2 (n = 1–8) clusters prefer a three-dimensional structure when n = 2 and n = 3 upwards, respectively, and they can be viewed as grown from the already observed Au
n−1M2 (M = Si, P). The relative stabilities of calculated Au
n
M2 (M = Si, P) clusters have been analyzed through the atomic average binding energy, fragmentation energy, second-order difference
of energy, and HOMO-LUMO gap. A pronounced odd-even alternative phenomenon indicates that the clusters with even-numbered
valence electrons possess a higher stability than their neighboring ones. For both systems, natural population analysis reveals
that electronic properties of dopant atoms in the corresponding configuration are mainly related to s and p states. We also investigated magnetic effects of clusters as a function of cluster size, however, their oscillatory magnetic
moments were found to vary inversely to the fragmentation energy, second-order difference of energy, and HOMO-LUMO gap. 相似文献
13.
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
14.
The structural and electronic properties of silver-doped gold clusters Au n Ag v (2?≤?n?≤?10; v?=?0,?±1) have been systematically investigated using density functional theory. The results show that the ground state optimal structures of the cationic and neutral clusters are found to be planar up to n?=?3 and 9, respectively. However, for the anionic clusters, no three-dimensional lowest-energy structures are obtained according to DFT calculations. The calculated binding energy and dissociation energy as a function of cluster size exhibit odd–even alternations. The natural population analysis indicates that in Au n Ag v clusters charges transfer from the Ag atom to the Au frames. The trends for the vertical detachment energies, adiabatic electron affinities, adiabatic ionization potentials, and chemical hardness of Au n Ag v clusters, as the cluster size increases, are studied in detail and compared with the available experimental data. 相似文献
15.
Yuhua Chi Lianming Zhao Xiaoqing Lu Changhua An Wenyue Guo Chi-Man Lawrence Wu 《Journal of nanoparticle research》2016,18(3):78
Density functional theory (DFT) has been applied to study the geometrical and electronic structures and the catalytic properties for NO oxidation of pure Pt and PtAu clusters. The calculated results suggest that Pt10 clusters shows the most stable structure among the pure Pt n (n = 2–13) clusters with the local maximum Δ2 E value. The doping of Au atoms reduces the stability of the clusters, and Pt6Au4 cluster has the most stable structure among Pt10?n Au n (n = 1–7) clusters, due to the closest band centers between Pt and Au atoms (0.83 eV) and the obvious s–p resonance peaks near the Fermi level. Pt6Au4 cluster displays the strongest activation of O2 molecules among Pt10?n Au n (n = 0–7) clusters, owing to the clear overlap between O 2p and Pt 6 s and Au 6 s near the Fermi level, and the more positive d band center than the others. The interaction between NO and metals changes slightly in NO/Pt10-nAun (n = 2–7) systems, which is weaker than that in NO/Pt9Au system, as a result of the decreasing resonance peaks of sp hybridization near the Fermi level. Compared to pure Pt10 cluster, the lower energy barriers and larger reaction energies on Pt6Au4 cluster suggest a higher catalytic activity of PtAu cluster for the O2 dissociation and NO oxidation reactions. Our study provides atomic-scale insights into the nature of the interfacial effect that determines NO oxidation on PtAu cluster catalysts. 相似文献
16.
The geometric structures, stabilities, and electronic properties of small size anionic [AunRb]? and Aun+1? (n = 1–10) clusters have been systematically investigated by using density functional theory. The optimised geometries show that the structures of [AunRb]? clusters favour the three-dimensional structure at n ≥ 8. The Rb atoms tend to occupy the most highly coordinated position and form the largest probable number of bonds with gold atoms. One Au atom capped on [Aun-1Rb]? structures is the dominant growth pattern for n = 2–8 and Rb atom capped on Aun? structures for n = 9–10. The averaged atomic bonding energies, fragmentation energies, second-order difference of energies, and highest occupied molecular orbital–lowest unoccupied molecular orbital gaps exhibit a pronounced even–odd alternations phenomenon. The charges in [AunRb]? clusters transfer from the Rb atoms to Aun host. In addition, it is found that the most favourable dissociation channel of the [AunRb]? clusters is to eject a Rb atom and the highest energy dissociation path is Rb? anion ejection. 相似文献
17.
A systematic study of the X2Aun (X = La, Y, Sc; n = 1–9) clusters are performed by using the density functional theory at TPSS level. The structures, stabilities, electronic, and magnetic properties are investigated in comparison with pure gold clusters. The results show that the transition points of the doped clusters from two-dimensional to three-dimensional structure are obviously earlier than gold clusters. The impurity X atoms tend to occupy the most highly coordinated position and form the largest probable number of bonds with gold atoms. In addition, the impurity atoms can strongly enhance the stabilities of gold clusters. It indicates that the impurity atoms dramatically affect the geometries and stabilities of the Aun clusters. The highest occupied molecular orbital–lowest occupied molecular orbital gap, vertical ionisation potential, and chemical hardness show that the X2Au6 clusters have higher stabilities than the others. In La2Au1–9, Y2Au1–7, and Sc2Au1–4 clusters, the charges transfer from X atoms to the Aun frames. The total magnetic moments of X2Aun clusters exist distinctly odd–even alternation behaviours except for La2Au4 and Sc2Au4 clusters. 相似文献
18.
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
19.
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
20.
采用基于密度泛函理论的BP86/CEP-121G (O原子采用6-311G**基组)方法,对ScnO (n=1—9)团簇的几何结构、能量与稳定性、电子结构性质及其随团簇尺寸的变化趋势进行了研究.随着团簇原子个数的增加,O原子从位于Scn团簇结构的边缘转变为占据团簇的内部位置.O原子的掺入增加了Scn团簇的稳定性,使其能隙升高,并改变了其稳定性及电子结构性质随团簇尺寸变化的规律;含有偶数个Sc原子的氧化物团簇比其周围邻近的含有奇数个Sc原子的氧化物团簇具有相对较高的稳定性.ScnO团簇电离势的理论计算值与实验值符合得较好,而其电子亲和势呈现振荡交替上升的变化趋势;用最大化学硬度规律等方法表征了ScnO氧化物团簇的稳定性和电子结构性质.
关键词:
nO团簇')" href="#">ScnO团簇
几何结构
电子性质
密度泛函理论 相似文献