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1.
本文选用密度泛函B3LYP方法在Lan L2DZ基组上对Au Gen+(n=2~9)团簇的几何结构和电子性质进行了理论研究,其中包括结构优化、平均键能、HOMO-LUMO能隙和电荷转移等。结果表明,随着锗原子数的不断增加,这些掺杂团簇逐渐形成了三维立体结构,并发现Au Ge7+和Au Ge9+两个掺杂团簇是相对稳定的,而且这些掺杂团簇的电荷转移主要是由金原子到锗原子骨架上。此外,还模拟了这些掺杂团簇的红外光谱,为以后实验研究提供有价值的理论参考。 相似文献
2.
The geometries, stabilities, electronic, and magnetic properties of AunSc clusters have been systematically investigated by density functional theory. The lowest energy structures of AunSc favor planar structure and the doped Sc atom does not disturb the frame of Aunclusters with n≤11. For n≥12, Sc atom is fully encapsulated by the Au cages. From theanalysis of the second-order energy difference, the fragmentation energies, vertical ionizationpotential, vertical electron affinity, and HOMO-LUMO gap, the clusters with odd Au atoms possess relatively higher stabilities than their neighbor size. The doping of Sc atom can greatly improve the stability and change the sequence of chemical activity for Aun. For n≤11, the total magnetic moments of AunSc appear the alternation between 0.00 and 1.00 μB. The total magnetic moments are quenched when Sc is trapped into the Au cages with n≥12. 相似文献
3.
Xiao Zhang Ling Guo Jian Guo Ning-Ning Ren 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(3):457-465
The binding energy, dissociation energy, ionization potentials, electron affinities, gap and stability of small Al n Pt (n = 1–15) clusters, in comparison with pure aluminum clusters have been systematically investigated by means of density functional calculations at the B3LYP level. The growth patten for Al n Pt clusters is that the Pt atom substituted the surface atom of the Al n + 1 clusters for n < 13. Starting from n = 13, the Pt atom completely falls into the center of the Al-frame. The Pt atom substituted the center atom of the Al n + 1 clusters to form the Pt-encapsulated Aln geometries for n > 13. We also find that the impurity Pt atom causes local structural distortion due to different atomic radii and different bonding characteristics. The clusters with total atom numbers of 2, 7, and 11 exhibit high stability. 相似文献
4.
Abdelhamid Soltani Abdel‐Ghani Boudjahem Mohammed Bettahar 《International journal of quantum chemistry》2016,116(5):346-356
The equilibrium geometries, relative stabilities, electronic and magnetic properties of small RhnCa (n = 1–9) clusters have been investigated by DFT calculations. The obtained results show that the three‐dimensional geometries are adopted for the lowest‐energy RhnCa clusters, and the doped Ca atom prefers locating on the surface of the cluster. Based on the analysis of the second‐order difference of energies, fragmentation energies and the HOMO‐LUMO energy gaps, we identify that the Rh4Ca, Rh6Ca, and Rh8Ca clusters are relatively more stable than their neighboring clusters, and the doping of Ca enhances the chemical reactivity of the pure Rhn clusters, suggesting that the RhnCa clusters can be used as nanocatalysts in many catalytic reactions. The magnetic moment for these clusters is mostly localized on the Rh atoms, and the doping Ca atom has no effect on the total magnetic moment of RhnCa clusters. The partial density of states, VIP, VEA, and η of these clusters in their ground‐state structures were also calculated and discussed. © 2015 Wiley Periodicals, Inc. 相似文献
5.
基于密度泛函理论(DFT)的B3LYP方法, 研究了TinO2和TinO2- (n=1-10)团簇的几何结构、电子结构以及磁性. 结果表明, 两个氧以分离的原子状态吸附在金属团簇的表面, 呈现出以一个钛原子为中心的O-Ti-O 的相邻吸附形式. 中性团簇和阴离子团簇的能量最低结构相似. 稳定性分析表明TinO2具有很高的稳定性, 特别是TiO2和Ti7O2. 此外, 详细讨论了团簇的电离势、电子亲和能、电子解离能和能隙. 基于最低能量结构, 讨论了团簇的磁性, 发现电荷从Ti 原子向O原子转移, 并且电荷转移主要发生在TinO2的Ti-3d、Ti-4s和O-2p轨道. 磁性团簇中反铁磁序占据主导, 磁矩主要来源Ti-3d电子的贡献, 而两个氧原子的贡献非常小. 相似文献
6.
First-principle density functional theory is used for studying the anion gold clusters doped with magnesium atom. By performing geometry optimizations, the equilibrium geometries, relative stabilities, and electronic and magnetic properties of [Au(n)Mg]? (n = 1-8) clusters have been investigated systematically in comparison with pure gold clusters. The results show that doping with a single Mg atom dramatically affects the geometries of the ground-state Au(n+1)? clusters for n = 2-7. Here, the relative stabilities are investigated in terms of the calculated fragmentation energies, second-order difference of energies, and highest occupied?lowest unoccupied molecular orbital energy gaps, manifesting that the ground-state [Au(n)Mg]? and Au(n+1)? clusters with odd-number gold atoms have a higher relative stability. In particular, it should be noted that the [Au?Mg]? cluster has the most enhanced chemical stability. The natural population analysis reveals that the charges in [Au(n)Mg]? (n = 2-8) clusters transfer from the Mg atom to the Au frames. In addition, the total magnetic moments of [Au(n)Mg]? clusters exhibit an odd-even oscillation as a function of cluster size, and the magnetic effects mainly come from the Au atoms. 相似文献
7.
The authors predict that the magnetic moment of the scandium clusters can not be efficiently enhanced with the encapsulation of Fe atom, which is different from previous works with Fe atom doped in Bn, Sin, and Gen clusters. It was found that starting from n=6, the growth patterns of the ground state structures of the ScnFe clusters are dominated by the octahedron structures with Fe atom falling into the center of the host framework. The calculated results manifest that doping of the Fe atom contributes to strengthening the stabilities of the scandium framework. Maximum peaks are observed for clusters of n=3, 6 and 8 on the size dependence of the second‐order energy differences, implying that these clusters possess relatively higher stability. The HOMO‐LUMO gap of the ScnFe clusters exhibits an oscillational odd‐even character with the local peaks of n=4, 6 and 8. Especially, there is the largest oscillation of the gap with n=4 and 5. Additionally, the doped Fe atom exhibits the antiferromagnetic alignment at n=4, 5, 7 and 9. Also, the quench of the magnetic moments as n=6, 8 and 10 may be ascribed to the model of close‐shell electrons. 相似文献
8.
合成了锌(II)与3,4-吡啶二羧酸和1,10-邻菲啰啉形成的配位聚合物[Zn(PDC)(phen)]n (1) (H2PDC=3,4-吡啶二羧酸, phen=1,10-邻菲啰啉), 对其进行了元素分析、红外光谱和X射线单晶衍射表征, 测定了晶体结构. 该聚合物属单斜晶系, P2(1)/n空间群, a=0.77136 nm, b=1.9757(4) nm, c=1.0680(2) nm, β=95.36(3)°, V=1.6205(6) nm3, Z=4, Dc=1.683 Mg/m3, Mr=410.68, F(000)=832, μ=1.55 mm-1, 最终偏离因子R1=0.0608, wR2=0.0967. 该化合物中Zn原子与来自两个PDC的三个羧基氧原子, 另外一个PDC的吡啶氮原子, 以及phen的两个氮原子配位, 形成的ZnN3O3八面体通过PDC桥联形成二维层状网络结构. 此外还研究了该聚合物的热性质和荧光性质. 相似文献
9.
Lu‐Jie Cao Hong‐Qi Ai Li‐Ming Zheng Su‐Na Wang Mei‐Juan Zhou Ji‐Feng Liu Chong Zhang 《International journal of quantum chemistry》2011,111(10):2416-2427
The interactions between the neutral and charged (?2, ?1, +1, and +2) Tin (n = 1–7) clusters and one O2 molecule were investigated by density functional theory. The calculated results show that the oxygen molecule is dissociative on the neutral Tin clusters. Geometrically, the two O atoms are distributed at the two sides across the neutral Tin cluster for n = 1–4 and the oxygen atom favors the three‐fold hollow site for n = 5, 6, and 7. The binding energy per atom (Eb) and energy gap (Egap) show higher stability and lower chemical activity of the neutral TinO2 (n = 1–7) systems compared with the corresponding Tin clusters. The adsorption energies (Ead) exhibit a continuously ascending tendency except for n = 4. The results of the addition of different charges (?2, ?1, +1, and +2) on the most stable neutral TinO2 (n = 1–7) systems indicate that their geometries are usually perturbed. The stabilities of the neutral TinO2 systems are enhanced by adding one negative charge. The strongest interaction of the charged Tin clusters (?2, ?1, +1, and +2) with O2 molecule is found at charge +2. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
10.
The geometries, magnetic properties and stabilities of the transition metal (TM) atoms encapsulated M2Si18 (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) clusters have been systematically calculated by using the density function theory with generalized gradient approximation. Only when the doping metal atom has no more than half‐full d electronic shell, a double hexagonal prism cage‐like M2Si18 structure could form. The total moments of M2Si18 are either 0 or 2μB. Co2Si18 is the most stable cluster among all 3d doped M2Si18 clusters. The model of shell closure at the TM atom may be helpful to understand the stability of M2Si18 clusters. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
11.
Tcn and Tcn@C70 Endohedral Metalofullerenes: ab initio Spin-density-functional Calculations
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Ab initio spin-density-functional calculations have been performed to study the equilibrium structural, electronic, and magnetic properties of Tcn and Tcn@C70 endohedral metalofullerenes. Our results indicate that C70 can encapsulate Tcn clusters with up to n=9 atoms. Except n=2, the formation of Tcn@C70 endohedral metalofullerenes is predicted to be exothermic when n≤5, while the encapsulation process becomes increasingly endothermic beyond n=5. When encapsulating into the C70 cage, the geometries as well as electronic structures of the Tc cluster undergo comparative changes. Especially, compared to the isolated Tcn clusters, the total magnetic moments of Tcn@C70 reduce significantly. The analyses of the orbital population, Hirshfeld population and density of states show that electrons transfer from the Tc cluster to the carbon cage through the Tc-C efficient hybridization, which is responsible for such reduction of the whole magnetism. 相似文献
12.
Dr. Vu Thi Ngan Prof. Ewald Janssens Dr. Pieterjan Claes Prof. Jonathan T. Lyon Dr. André Fielicke Prof. Dr. Minh Tho Nguyen Prof. Dr. Peter Lievens 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(49):15788-15793
We report on the structural, electronic, and magnetic properties of manganese‐doped silicon clusters cations, SinMn+ with n=6–10, 12–14, and 16, using mass spectrometry and infrared spectroscopy in combination with density functional theory computations. This combined experimental and theoretical study allows several structures to be identified. All the exohedral SinMn+ (n=6–10) clusters are found to be substitutive derivatives of the bare Sin+1+ cations, while the endohedral SinMn+ (n=12–14 and 16) clusters adopt fullerene‐like structures. The hybrid B3P86 functional is shown to be appropriate in predicting the ground electronic states of the clusters and in reproducing their infrared spectra. The clusters turn out to have high magnetic moments localized on Mn. In particular the Mn atoms in the exohedral SinMn+ (n=6–10) clusters have local magnetic moments of 4 μB or 6 μB and can be considered as magnetic copies of the silicon atoms. Opposed to other 3d transition‐metal dopants, the local magnetic moment of the Mn atom is not completely quenched when encapsulated in a silicon cage. 相似文献
13.
Meng Zhang Li-Ming He Li-Xia Zhao Xiao-Juan Feng Wei Cao You-Hua Luo 《Journal of Molecular Structure》2009,911(1-3):65-69
The geometries, electronic, and magnetic properties of the Au7Hn (n = 1–10) clusters have been systematically investigated by using relativistic all-electron density functional theory with generalized gradient approximation. It is found that the Au7 on the whole retains its triangle structure after hydrogen atoms adsorption and adsorbing hydrogen atoms can stabilize the Au7 structure. The Au7H7 cluster is much higher stability than the neighboring clusters. The pronounced even–odd alternation of the magnetic moments is observed in the Au7Hn systems indicating Au7Hn clusters possess tunable magnetic properties by adding even or odd number of H atoms. 相似文献
14.
Ling Guo 《Journal of Cluster Science》2013,24(2):575-589
The growth behavior of (GaAl) n (n = 1–12) and the chemisorptions of hydrogen on the ground state geometries have been studied with the three-parameter hybrid generalized gradient approximation due to Becke-Lee–Yang–Parr (B3LYP). The dissociation energy, the second-order energy differences, and the HOMO–LUMO gaps indicate that the magic numbers of the calculated (GaAl) n clusters are n = 4 and 6. To my knowledge, this is the first time that a systematic study of chemisorptions of hydrogen on gallium aluminum clusters. The onefold top site of aluminum atom is identified to be the most favorable chemisorptions site for one hydrogen chemisorptions on most (GaAl) n clusters. In general, dissociative chemisorptions of a hydrogen molecule on a top site of aluminum atom is found common for all sizes clusters considered here except for (GaAl) n (n = 1–3) clusters. The stability of the (GaAl) n H m complexes shows that both large second-order difference and large fragmentation energies for (GaAl)10H2 and (GaAl)11H2 make these species behaving like magic clusters. 相似文献
15.
报道四核铜配合物[Cu2L2][Cu(pht)2]2[Hpht:苯妥英,即5,5-二苯基-2,2咪唑烷酮;L:N-(3-氨基丙基)二乙醇胺]的溶剂热合成、晶体结构及其性质研究.该晶体属单斜晶系,P21/n空间群,晶胞参数:a=0.9240(1)nm,b=2.4559(2)nm,c=1.5572(2)nm,β=97.489(2)o,V=3.5035(7)nm3,Dc=1.499Mg/m3(g/cm3),Z=2,F(000)=1636,μ=1.270mm-1,R1=0.0503,wR2=0.1135[I2σ(I)],GOF=1.014.XPS结合X射线单晶结构分析,表明该配合物分子有混价铜组成,包括两个Cu(I)和两个Cu(II),其中每个Cu(I)分别与两个苯妥英配体提供的氮原子配位,N—Cu(I)—N的夹角为177.1°,每个Cu(II)与L配体的五个配位原子配位(N2O3),形成一个稍变形四方锥结构,两个Cu(II)通过N-(3-氨基丙基)二乙醇胺中的一个羟基氧桥连接形成双核阳离子,琼脂扩散法测试结果表明配合物、配体和铜盐对3种受试细菌均有一定的活性.配合物与DNA的相互作用测定研究表明,该配合物是以插入方式与小牛胸腺DNA结合. 相似文献
16.
采用基于第一性原理的分子动力学和量子力学相结合的方法, 对W3O9团簇在经Li 和Al 原子掺杂的MgO(001)表面的负载构型、稳定性以及体系的电子结构进行了系统研究. 结果表明, 当掺杂发生在表层时, 杂质原子的类型对W3O9团簇的负载构型有显著影响. 对于缺电子的Li 掺杂, 负载后W3O9团簇环状构型并不稳定, 转化为链状结构; 而Al 原子的掺杂则使得MgO(001)表面电子富余, 此时W3O9团簇存在平躺和垂直两种吸附方式, 二者能量稳定性相近, 其中前者存在同时与三个W原子成键的帽氧结构. 当掺杂发生在次表层时, 两种掺杂体系W3O9的负载构型相似, 团簇仍保持环状结构并倾向于采用垂直方式沉积在表面上. 与Li 掺杂体系相比, 富电子的Al 掺杂可显著增强W3O9与MgO(001)表面之间的结合能力, 负载后有较多电子从表面转移到团簇中特定的W原子上, 这将对W3O9团簇的催化性能产生显著影响. 相似文献
17.
The geometric and electronic structures of Si(n), Si(n) (+), and AlSi(n-1) clusters (2< or =n< or =13) have been investigated using the ab initio molecular orbital theory under the density functional theory formalism. The hybrid exchange-correlation energy function (B3LYP) and a standard split-valence basis set with polarization functions [6-31G(d)] were employed for this purpose. Relative stabilities of these clusters have been analyzed based on their binding energies, second difference in energy (Delta (2)E) and fragmentation behavior. The equilibrium geometry of the neutral and charged Si(n) clusters show similar structural growth. However, significant differences have been observed in the electronic structure leading to their different stability pattern. While for neutral clusters, the Si(10) is magic, the extra stability of the Si(11) (+) cluster over the Si(10) (+) and Si(12) (+) bears evidence for the magic behavior of the Si(11) (+) cluster, which is in excellent agreement with the recent experimental observations. Similarly for AlSi(n-1) clusters, which is isoelectronic with Si(n) (+) clusters show extra stability of the AlSi(10) cluster suggesting the influence of the electronic structures for different stabilities between neutral and charged clusters. The ground state geometries of the AlSi(n-1) clusters show that the impurity Al atom prefers to substitute for the Si atom, that has the highest coordination number in the host Si(n) cluster. The fragmentation behavior of all these clusters show that while small clusters prefers to evaporate monomer, the larger ones dissociate into two stable clusters of smaller size. 相似文献
18.
Energy Stabilities,Magnetic Properties,and Electronic Structures of Diluted Magnetic Semiconductor Zn1-xMnxS(001) Thin Films
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We investigate the electronic and magnetic properties of the diluted magnetic semiconductors Zn1-xMnxS(001) thin films with different Mn doping concentrations using the total energy density functional theory. The energy stability and density of states of a single Mn atom and two Mn atoms at various doped configurations and different magnetic coupling state were calculated. Different doping configurations have different degrees of p-d hybridization, and because Mn atoms are located in different crystal-field environment, the 3d projected densities of states peak splitting of different Mn doping configurations are quite different. In the two Mn atoms doped, the calculated ground states of three kinds of stable configurations are anti-ferromagnetic state. We analyzed the 3d density of states diagram of three kinds of energy stability configurations with the two Mn atoms in different magnetic coupling state. When the two Mn atoms are ferromagnetic coupling, due to d-d electron interactions, density of states of anti-bonding state have significant broadening peaks. As the concentration of Mn atoms increases, there is a tendency for Mn atoms to form nearest neighbors and cluster around S. For such these configurations, the antiferromagnetic coupling between Mn atoms is energetically more favorable. 相似文献
19.
Structural and Magnetic Properties of CoGen− (n=2–11) Clusters: Photoelectron Spectroscopy and Density Functional Calculations
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Xiao‐Jiao Deng Dr. Xiang‐Yu Kong Dr. Xi‐Ling Xu Dr. Hong‐Guang Xu Prof. Dr. Wei‐Jun Zheng 《Chemphyschem》2014,15(18):3987-3993
A series of cobalt‐doped germanium clusters, CoGen?/0 (n=2–11), are investigated by using anion photoelectron spectroscopy combined with density functional theory calculations. For both anionic and neutral CoGen (n=2–11) clusters, the critical size of the transition from exo‐ to endohedral structures is n=9. Natural population analysis shows that there is electron transfer from the Gen framework to the Co atom at n=7–11 for both anionic and neutral CoGen clusters. The magnetic moments of the anionic and neutral CoGen clusters decrease to the lowest values at n=10 and 11. The transfer of electrons from the Gen framework to the Co atom and the minimization of the magnetic moments are related to the evolution of CoGen structures from exo‐ to endohedral. 相似文献
20.
Marcella Bini Pietro Galinetto Stefania Ferrari Vincenzo Massarotti 《Journal of solid state chemistry》2009,182(7):1972-1981
Different solid state and sol-gel preparations of undoped and Mn substituted cathode material LiFePO4 are investigated. Li3PO4, Fe2P2O7 and Li4P2O7 are detected and quantified by XRPD only in solid state synthesis. In addition, micro-Raman spectra reveal low amount of different iron oxides clusters. EPR data, combined with the results of magnetization measurements, evidence signals from Fe3+ ions in maghemite nanoclusters, and in Li3Fe2(PO4)3. The sol-gel synthesis, showing the lowest amount of impurity phases, seems the most suitable to obtain a promising cathode material. The structural refinement gives new insights into the cation distribution of the Mn doped triphylite structure: (i) about 85% of Mn2+ ions substitutes Fe2+, the remaining 15% being located on the Li site, thus suggesting a structural disorder also confirmed by EPR and micro-Raman results; (ii) Mn ions on the Li site are responsible for the observed slight cell volume expansion. 相似文献