Articles de revues : « Electronic Properties - Metal Clusters »

1

Pastor, G. M. « Electronic properties of divalent-metal clusters ». Zeitschrift f�r Physik D Atoms, Molecules and Clusters 19, n^o 1-4 (mars 1991) : 165–67. http://dx.doi.org/10.1007/bf01448282.

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Jena, P., S. N. Khanna et B. K. Rao. « CLUSTERS WITH NOVEL PROPERTIES ». International Journal of Modern Physics B 06, n^o 23n24 (décembre 1992) : 3657–66. http://dx.doi.org/10.1142/s0217979292001717.

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The size specific nature of the electronic and structural properties of small metal clusters is reviewed. Three specific examples are illustrated: the nature of hydrogen interaction with neutral and charged metal clusters, the stability and electronic properties of metal-carbon complexes and the role of electron shell filling and close atomic packing on synthesizing very stable and chemically inert clusters.

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Maryam Darvishpour, Maryam Darvishpour, et Mohammad Hossein Fekri Mohammad Hossein Fekri. « Investigation of the Magnetic and Electronic Properties of Copper Nanocluster Cu14 Contaminated with Fe, Ni and Co ». Journal of the chemical society of pakistan 42, n^o 3 (2020) : 399. http://dx.doi.org/10.52568/000647.

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We have presented density functional calculations of the electronic structures and magnetic properties of bimetallics nanoclusters Cu14-nMn (n=1-3) (M=Fe, Ni and Co) in the FCC crystal structure. For the calculations of the physical properties of the compounds, we have used the full potential linearized augmented plane wave method. The magnetic nature, semiconducting, half metallicity and metalloid of transition metals clusters in the FCC crystal structure are investigated. Results show that studied systems have ferromagnetic properties against Cu14Cluster. It is found that band gap of the clusters decreases with doping of atoms compared to pure cluster Cu14, Particularly for Fe. These calculations show that Cu14 and Cu12Co2 are metals, while Cu13Fe, Cu12Fe2, Cu13Co, Cu11Co3 and Cu11Ni3 are half-metals and Cu11Fe3 and Cu12Ni2 are metalloid. Between these clusters, Cu13Ni is semiconductor. The spin polarization and the magnetic moment of the systems are dependent on number and type of the host transition metal atoms. The Cu13Ni has maximum spin polarization and stability. These results provide a new candidate for applications this series of compounds as dilute magnetic clusters and half-metal in spintronic devices.

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Maryam Darvishpour, Maryam Darvishpour, et Mohammad Hossein Fekri Mohammad Hossein Fekri. « Investigation of the Magnetic and Electronic Properties of Copper Nanocluster Cu14 Contaminated with Fe, Ni and Co ». Journal of the chemical society of pakistan 42, n^o 3 (2020) : 399. http://dx.doi.org/10.52568/000647/jcsp/42.03.2020.

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We have presented density functional calculations of the electronic structures and magnetic properties of bimetallics nanoclusters Cu14-nMn (n=1-3) (M=Fe, Ni and Co) in the FCC crystal structure. For the calculations of the physical properties of the compounds, we have used the full potential linearized augmented plane wave method. The magnetic nature, semiconducting, half metallicity and metalloid of transition metals clusters in the FCC crystal structure are investigated. Results show that studied systems have ferromagnetic properties against Cu14Cluster. It is found that band gap of the clusters decreases with doping of atoms compared to pure cluster Cu14, Particularly for Fe. These calculations show that Cu14 and Cu12Co2 are metals, while Cu13Fe, Cu12Fe2, Cu13Co, Cu11Co3 and Cu11Ni3 are half-metals and Cu11Fe3 and Cu12Ni2 are metalloid. Between these clusters, Cu13Ni is semiconductor. The spin polarization and the magnetic moment of the systems are dependent on number and type of the host transition metal atoms. The Cu13Ni has maximum spin polarization and stability. These results provide a new candidate for applications this series of compounds as dilute magnetic clusters and half-metal in spintronic devices.

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Rao, B. K., S. N. Khanna et P. Jena. « Structural and electronic properties of compound metal clusters ». Zeitschrift f�r Physik D Atoms, Molecules and Clusters 3, n^o 2-3 (juin 1986) : 219–22. http://dx.doi.org/10.1007/bf01384810.

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Oleshko, Vladimir P., Peter A. Crozier, Nick Schryvers et Michail Vargaftik. « Mesostructure Of Pd And Pt Nanoclusters Chemically Stabilized With Phosphide And Phenanthroline Ligands : Hrtem And Aem Characterization ». Microscopy and Microanalysis 5, S2 (août 1999) : 184–85. http://dx.doi.org/10.1017/s1431927600014240.

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The noble metal (Me = Au, Pd, Rh, and Pt) polynuclear coordination compounds of Chini’s type eventually serve as a remarkable bridge between molecular clusters and metal colloids. The sizes of the metal cores of the cluster compounds are close to lower sizes of colloidal metal particles. However, chemically stabilized nanoclusters have a distinct ligand environment with a definite stoichiometry inherent to molecular clusters. Interest in structures of the cluster compounds has increased in recent years in view of their unique selective catalytic properties under mild conditions, which, in principle, open a way to the development of a new branch of catalysis by metal clusters, quantum-size effects in the thermodynamic properties, and applications as nano-sized electronic devices (quantum dots). A key feature in structural characterization of such species (they are amorphous solids usually unsuitable for x-ray diffraction analysis) is to understand the relations between the atomic arrangement, electronic structure and chemical reactivity.

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Phaahla, TM, PE Ngoepe, RA Catlow et HR Chauke. « The effect of doping with pt impurity on ti clusters : a density functional theory study ». Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 40, n^o 1 (24 janvier 2022) : 75–78. http://dx.doi.org/10.36303/satnt.2021cosaami.15.

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Transition metal nanoclusters have been greatly investigated in various areas such as catalysis, energy conversion and sensing due to their unique chemical, optical, structural, and electronic properties. Doping monometallic clusters with other metals offer the opportunity to enhance these properties. Extensive work has been done on late transition metal clusters i.e., noble and platinum metals. However, less work has been done on titanium metal clusters. The structural properties of TiN-1Pt (N = 2 – 16) clusters have been investigated using the density functional theory method with the PBEsol exchange-correlation functional. Our results showed that the binding energies for both systems decrease with cluster size N. The Ti12Pt cluster was found to be more enhanced in comparison with pure Ti revealed by the binding energy, relative stability and dissociation energy. Furthermore, binding, relative stability and dissociation energies were found to be enhanced as compared to the energies for Ti monometallic clusters.

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GOODMAN, D. W. « CATALYSIS BY METALS : FROM EXTENDED SINGLE CRYSTALS TO SMALL CLUSTERS ». Surface Review and Letters 01, n^o 04 (décembre 1994) : 449–55. http://dx.doi.org/10.1142/s0218625x94000424.

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Model oxide-supported metal cluster catalysts have been prepared by evaporating the corresponding metal (e.g., Cu, Pd, Ni) onto a oxide thin film (~100 Å), which in turn is supported on a refractory metal (Mo, W, Ta) surface. The deposited metal films, upon annealing, form small metallic clusters on the oxide surface whose size are dependent upon the initial metal film thickness. The surface structures and cluster morphologies have been characterized using scanning probe microscopies, temperature-programed desorption, X-ray, and ultraviolet photoemission; and high-resolution electron energy loss spectroscopy/infrared reflection-absorption spectroscopy of adsorbed carbon monoxide. The catalytic properties of these clusters have also been investigated with respect to several reactions including CO/O 2 and CO/NO. The chemical and electronic properties of the metal clusters with respect to size are compared to the analogous properties of extended single crystal surfaces.

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Nguyen, Hong Van, That Van Nguyen, Bong Thi Le, Huong Thi Thanh Do et Truc Thi Thanh Huynh. « Theoretical study on structures and electronic properties of Na8TM clusters (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) ». Science and Technology Development Journal - Natural Sciences 2, n^o 2 (16 mai 2019) : 54–61. http://dx.doi.org/10.32508/stdjns.v2i2.734.

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Na8TM (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) clusters are optimized by DFT calculations combining the Triple zeta valence plus polarization (TZVP) method to determine magnetic torque values on orbits, point groups, electron structures, and spin density images of the atomic groups. The results indicate that Na atoms in Na8TM cluster strongly affect the total magnetic moment of the whole group of atoms. In a cluster, each Na atom contributes one electron which combines with valence electron of transition metal for creating a sum of valence electron of the cluster. Atomic groups with the highest magnetic moments are Na8V (5 B) and non-magnetic clusters are Na8Ni and Na8Zn. The electronic structure and magnetic properties of the clusters resemble those of some metals and transition metal ions. This study will orientate to substitution in magnetic materials by metal clusters.

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NOZUE, Y., T. KODAIRA, S. OHWASHI, N. TOGASHI et O. TERASAKI. « FERROMAGNETISM OF ALKALI-METAL CLUSTERS INCORPORATED IN THE PERIODIC SPACE OF ZEOLITE LTA ». Surface Review and Letters 03, n^o 01 (février 1996) : 701–6. http://dx.doi.org/10.1142/s0218625x96001261.

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Magnetic properties are reported for rubidium and potassium clusters arrayed in a simple-cubic structure in zeolite LTA crystal. A ferromagnetism is observed, although no magnetic element is contained there. The result clearly indicates the intercluster interaction. The ferromagnetic properties vary depending on the average number of ns electrons of cluster. Optical properties reveal quantum electronic levels of cluster. The ferromagnetism is interpreted qualitatively in terms of the itinerant electron model based on the quantum levels of cluster. The magnetic properties of various clusters observed in zeolites are discussed from the microscopic point of view.

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Li, Zhi, Zhen Zhao, Qi Wang et Tao-Tao Shao. « Structures and electronic properties of the transition metal-adsorbed B36 clusters ». Modern Physics Letters B 34, n^o 34 (11 août 2020) : 2050387. http://dx.doi.org/10.1142/s021798492050387x.

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Metal doping is considered as an effective method to stabilize the structures and optimize the properties of boron clusters. The structures and electronic properties of the [Formula: see text] clusters have been calculated at the Perdew–Burkle–Ernzerhof (PBE) level. The results reveal that the Cu atoms for the [Formula: see text] clusters unexpectedly enter the [Formula: see text] clusters. Ti, V, Co, Ni, Zr, Hf, Ta and W can obviously increase the structural stability of pristine [Formula: see text] clusters. The Ti, Cr, Fe, Ni and Zn; Y, Ru and Ag; Lu, Ta, Ir and Au-adsorbed [Formula: see text] clusters display higher kinetic activity than other [Formula: see text] clusters. The d orbital electrons of the TM atoms will significantly affect the distributions of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) states of pristine [Formula: see text] clusters. All the TM–B bonds of the [Formula: see text] clusters display covalent characters.

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Bulbula, Shimeles T., et Hagos W. Zeweldi. « Density Functional Study of Electronic and Structural Properties of Gold-Cadmium Selenide/Telluride Nanoclusters ». Advances in Materials Science and Engineering 2015 (2015) : 1–9. http://dx.doi.org/10.1155/2015/847693.

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Semiconductor nanowires are one class of building blocks that show promise for application in nanoscale electronics. Metal-semiconductor nanowire helps to improve the electrical properties or create unique ones. Electronic and structural properties of cadmium selenide/telluride connected to gold electrode clusters have been the focus of this research due to their importance in constructing fast microelectric devices. The simulations were carried out by using VASP (ViennaAb-InitioSimulation Package) which utilizes the method of density functional theory (DFT) and plane wave basis set. Optimization was performed to obtain the minimum energy structure. In this research paper the result shows that the HOMO-LUMO gaps for the minimum energy cadmium selenide/telluride connected to gold electrodes decrease as cluster size increases, whereas the binding energy shows a reverse relationship with the cluster size. However, a few clusters show special properties like AuCd2Se3and AuCd2Te3clusters.

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Bui, Thanh Tho, Khung Moc Trang et Hong Van Nguyen. « Study on structures and electronic properties of NaxV (x=1-12) atomic clusters ». Science and Technology Development Journal 17, n^o 4 (31 décembre 2014) : 83–91. http://dx.doi.org/10.32508/stdj.v17i4.1559.

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Superatoms, novel entities being studied extensively in recent years, can be stabilized by mixing with transition metal atoms. The aim of this paper is to present some recent theoretical results on the application of quantum calculations for examining the atomic clusters NaxV (x=1-12) made from the mixing of Nax superatoms with vanadium transition metal atom. Optimized structures of NaxV, NaxV+ and NaxV- are determined by using the TPSSTPSS / DZVP DFT calculations. Characteristics of optimized structures, as point group symmetry, chemical hardness (η), absolute electronegativity (χ), electrophilicity index (ω), fragmentation energy (Ef), secondary energy (∆2E), are calculated. The obtained results point out that among different structures of an atomic cluster, the more negative total energy the more stable structure and the Na8V cluster is the most stable in NaxV (x=1-12) clusters.

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Cappellini, Giancarlo, Andrea Bosin, Giovanni Serra, Jürgen Furthmüller, Friedhelm Bechstedt et Silvana Botti. « Electronic and Optical Properties of Small Metal Fluoride Clusters ». ACS Omega 5, n^o 22 (27 mai 2020) : 13268–77. http://dx.doi.org/10.1021/acsomega.0c01317.

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Finocchi, Fabio, et Claudine Noguera. « Metal segregation and electronic properties of lithium suboxide clusters ». Physical Review B 57, n^o 23 (15 juin 1998) : 14646–49. http://dx.doi.org/10.1103/physrevb.57.14646.

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16

Roduner, Emil. « Symmetry and Electronic Properties of Metallic Nanoclusters ». Symmetry 15, n^o 8 (27 juillet 2023) : 1491. http://dx.doi.org/10.3390/sym15081491.

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Spherical nanoclusters with countable member atoms and delocalized valence orbitals are superatoms with properties analogous to those of simple atoms. This is reflected, in particular, in their optical spectra and magnetic properties, in a similar sense to transition metal ions and complexes. Clusters can be of low-spin or high-spin with considerable contributions to magnetism by the large cluster orbital magnetic moment. Due to the large radius of the clusters, they can be diamagnetic with an unusually high diamagnetic susceptibility. Gold and platinum, which in the bulk are non-magnetic, show pronounced superparamagnetism associated with their high-spin nature, and the magnetic moment can be trapped in symmetry-breaking environments so that hysteresis pertains far beyond room temperature. A significant deviation from hydrogen-like orbitals results from the shape of the confining potential, which has the effect that the orbital quantum number ℓ is not limited to values less than the principal quantum number n.

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TIGGESBÄUMKER, JOSEF, LARS KÖLLER et KARL-HEINZ MEIWES-BROER. « STATIC POLARIZABILITIES OF CHARGED SILVER METAL CLUSTERS EXTRACTED FROM THE OPTICAL SPECTRA ». Surface Review and Letters 03, n^o 01 (février 1996) : 509–13. http://dx.doi.org/10.1142/s0218625x96000929.

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The use of sum rules appears to be a powerful tool for obtaining experimental data on static properties of charged metal clusters which are currently not available. For this purpose the optical spectra of the clusters must be known. The measured absorption profiles of sputtered, i.e. hot, [Formula: see text] and [Formula: see text] which have been measured in our group give information about the desired properties. The extracted static polarizabilities show a distinct shell structure which reflects the overall electronic shape of the cluster. A comparison is made with AgN and positive alkali metal clusters. The polarizabilities of closed-shell [Formula: see text] and [Formula: see text] are in reasonable agreement with SIC-LDA corrected RPA polarizabilities.

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Dai, Ying, Bai Biao Huang, Run Long et Lin Yu. « Theoretical Study of Differences between Surface and Bulk Electronic States in Cu Clusters ». Solid State Phenomena 121-123 (mars 2007) : 1189–92. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.1189.

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The size-dependent electronic structures of metal clusters Cun (n=2-20) have been calculated using density functional theory method. The results reveal that their electronic properties are almost the same as bulk material if the cluster size larger than a critical value. The properties can be understood by a surface-noncrystalline-layer model that composed of an interior crystalline-like core and an outer surface noncrystalline layer.

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Miyazaki, T., H. Hiura et T. Kanayama. « Electronic properties of transition-metal-atom doped Si cage clusters ». European Physical Journal D - Atomic, Molecular and Optical Physics 24, n^o 1-3 (1 juin 2003) : 241–44. http://dx.doi.org/10.1140/epjd/e2003-00121-x.

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Zhang, Yuwei, Ping Song, Tiankai Chen, Xiaodong Liu, Tao Chen, Zhemin Wu, Yong Wang, Jianping Xie et Weilin Xu. « Unique size-dependent nanocatalysis revealed at the single atomically precise gold cluster level ». Proceedings of the National Academy of Sciences 115, n^o 42 (1 octobre 2018) : 10588–93. http://dx.doi.org/10.1073/pnas.1805711115.

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Atomically precise metal clusters have attracted increasing interest owing to their unique size-dependent properties; however, little has been known about the effect of size on the catalytic properties of metal clusters at the single-cluster level. Here, by real-time monitoring with single-molecule fluorescence microscopy the size-dependent catalytic process of individual Au clusters at single-turnover resolution, we study the size-dependent catalytic behaviors of gold (Au) clusters at the single-cluster level, and then observe the strong size effect on the catalytic properties of individual Au clusters, in both catalytic product formation and dissociation processes. Surprisingly, indicated by both experiments and density functional theory (DFT) calculations, due to such a unique size effect, besides observing the different product dissociation behaviors on different-sized Au clusters, we also observe that small Au clusters [i.e., Au15(MPA)13; here, MPA denotes 3-mercaptopropionic acid] catalyze the product formation through a competitive Langmuir–Hinshelwood mechanism, while those relatively larger Au clusters [e.g., Au18(MPA)14 and Au25(MPA)18] or nanoparticles catalyze the same process through a noncompetitive Langmuir–Hinshelwood mechanism. Such a size effect on the nanocatalysis could be attributed intrinsically to the size-dependent electronic structure of Au clusters. Further analysis of dynamic activity fluctuation of Au clusters reveals more different catalytic properties between Au clusters and traditional Au nanoparticles due to their different size-dependent structures.

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Cox, D. M., B. Kessler, P. Fayet, W. Eberhardt, Z. Fu, D. Sondericher, R. Sherwood et A. Kaldor. « Chemical and electronic properties of size selected metal clusters : XPS studies of gold clusters ». Nanostructured Materials 1, n^o 2 (mars 1992) : 161–65. http://dx.doi.org/10.1016/0965-9773(92)90070-e.

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Liu, Wenhua, Wei Hu, Yan Liang, Qinghua Zhou, Kerong He et Haiqing Wan. « The first-principles calculation on electronic transport properties of Al2N2 clusters ». International Journal of Modern Physics B 32, n^o 29 (20 novembre 2018) : 1850326. http://dx.doi.org/10.1142/s0217979218503265.

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In this paper, we have studied the electronic transport behavior of the system formed by the Al2N2 cluster and the Al(100)-3 × 3 electrodes by using the first principle based on nonequilibrium Green’s function (NEGF). The total energies and the equilibrium conductances of the system are calculated at different distances between the clusters and the electrodes, and the results show that the equilibrium conductance is 0.1335 G0 and the total energy is the lowest at d = 2.8 Å (d means the distance between the Al2N2 cluster and the electrodes). When d increases, the equilibrium conductance decreases. In the bias voltage range of [−1 V, 1 V], the system has the electrical characteristics similar to the metal when the d is 2.0, 2.4, 2.8, 3.2 and 3.5 Å.

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Prakash, Rini, Jean-François Halet et Sundargopal Ghosh. « Polyhedral [M2B5] Metallaborane Clusters and Derivatives : An Overview of Their Structural Features and Chemical Bonding ». Molecules 25, n^o 14 (12 juillet 2020) : 3179. http://dx.doi.org/10.3390/molecules25143179.

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A large number of metallaborane clusters and their derivatives with various structural arrangements are known. Among them, M2B5 clusters and derivatives constitute a significant class. Transition metals present in these species span from group 4 to group 7. Their structure can vary from oblatonido, oblatoarachno, to arachno type open structures. Many of these clusters appear to be hypoelectronic and are often considered as ‘rule breakers’ with respect to the classical Wade–Mingos electron counting rules. This is due to their unique highly oblate (flattened) deltahedral structures featuring a cross-cluster M−M interaction. Many theoretical calculations were performed to elucidate their electronic structure and chemical bonding properties. In this review, the synthesis, structure, and electronic aspects of the transition metal M2B5 clusters known in the literature are discussed. The chosen examples illustrate how, in synergy with experiments, computational results can provide additional valuable information to better understand the electronic properties and electronic requirements which govern their architecture and thermodynamic stability.

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Makov, Guy, et Abraham Nitzan. « On the nonclassical asymptotic behavior of electronic properties in metal clusters ». Journal of Chemical Physics 95, n^o 12 (15 décembre 1991) : 9024–27. http://dx.doi.org/10.1063/1.461233.

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Ebert, H., S. Bornemann, J. Minár, M. Ko[sbreve]uth, O. [Sbreve]ipr, P. H. Dederichs, R. Zeller et I. Cabria. « Electronic and magnetic properties of free and supported transition metal clusters ». Phase Transitions 78, n^o 1-3 (janvier 2005) : 71–83. http://dx.doi.org/10.1080/01411590412331316726.

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Parida, Prakash, Anasuya Kundu et Swapan K. Pati. « The Electronic and Magnetic Properties of a Few Transition-Metal Clusters ». Journal of Cluster Science 20, n^o 2 (12 février 2009) : 355–64. http://dx.doi.org/10.1007/s10876-009-0241-x.

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Li, Zhi, Tao-Tao Shao et Zhen Zhao. « Structures, electronic and magnetic properties of transition metals-doped Mg9O9 tubular clusters ». International Journal of Modern Physics B 34, n^o 21 (20 août 2020) : 2050211. http://dx.doi.org/10.1142/s0217979220502112.

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The structures, electronic and magnetic attributes of the transition metal (TM) doping Mg9O9 tubular clusters have been investigated using the PBE functional. The results display that the ScMg9O9 and NiMg9O9 clusters are more structurally stable than the other TMMg9O9 clusters. An Sc atom replaces the Mg atom at the edge site of the Mg9O9 clusters, which leads to the Mg atom transferring to the top of an adjacent O atom. Ni atom prefers to occupy the bridge site of the Mg–O bond at a side of the Mg9O9 clusters. VMg9O9 and FeMg9O9 display more kinetic activity than the other TMMg9O9 clusters. The TM atoms lost certain electrons except for Co, Cu and Zn. The maximum spin value of the TM atoms for the ground-state TMMg9O9 clusters occurs at Mn.

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Fantucci, P., V. Bonačić-Koutecký et J. Koutecký. « General properties of the electronic structure of alkali metal clusters and Ia-IIa mixed clusters ». Zeitschrift für Physik D Atoms, Molecules and Clusters 12, n^o 1-4 (mars 1989) : 307–14. http://dx.doi.org/10.1007/bf01426963.

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Li, Zhi, Zhen Zhao et Tao-Tao Shao. « Structures, electronic and magnetic properties of transition metal atoms encapsulated in Si12C12 cage ». Modern Physics Letters B 34, n^o 29 (16 juin 2020) : 2050320. http://dx.doi.org/10.1142/s0217984920503200.

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The structures, stability, electronic and magnetic properties of the TM@Si[Formula: see text]C[Formula: see text] clusters have been calculated by using PBE functional. The results indicate that only for the TM@Si[Formula: see text]C[Formula: see text] (TM[Formula: see text]Zn, Y, Ag, Cd, Lu, Au and Hg) clusters, TM atoms are nearly located at the center of the Si[Formula: see text]C[Formula: see text] cages. As for other TM@Si[Formula: see text]C[Formula: see text] clusters, TM atoms approach one side of the Si[Formula: see text]C[Formula: see text] cages. The structural stability of the Ti@Si[Formula: see text]C[Formula: see text], Ti@Si[Formula: see text]C[Formula: see text], Zr@Si[Formula: see text]C[Formula: see text], Nb@Si[Formula: see text]C[Formula: see text], Hf@Si[Formula: see text]C[Formula: see text], Ta@Si[Formula: see text]C[Formula: see text], W@Si[Formula: see text]C[Formula: see text] and Os@Si[Formula: see text]C[Formula: see text] is higher than that of the Si[Formula: see text]C[Formula: see text] cages. All TM@Si[Formula: see text]C[Formula: see text] clusters display covalent bond characteristics. The spins of the TM atoms in the TM@Si[Formula: see text]C[Formula: see text] cages are dramatically quenched and only the V@Si[Formula: see text]C[Formula: see text] and Cr@Si[Formula: see text]C[Formula: see text] clusters remain −1.474 [Formula: see text] and 1.638 [Formula: see text], respectively.

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Prats, Hector, et Michail Stamatakis. « Atomistic and electronic structure of metal clusters supported on transition metal carbides : implications for catalysis ». Journal of Materials Chemistry A 10, n^o 3 (2022) : 1522–34. http://dx.doi.org/10.1039/d1ta08468b.

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Several materials composed of metal nanoclusters supported on transition metal carbides (TMCs) are studied via density functional theory, in view of the promising catalytic properties demonstrated experimentally for selected TMC–metal combinations.

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Koirala, Pratik, Mary Willis, Boggavarapu Kiran, Anil K. Kandalam et Puru Jena. « Superhalogen Properties of Fluorinated Coinage Metal Clusters ». Journal of Physical Chemistry C 114, n^o 38 (21 juillet 2010) : 16018–24. http://dx.doi.org/10.1021/jp101807s.

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Yuan, Shijun, Xueli Wang, Pai Li, Chuanhui Wang et Songliu Yuan. « Structural, wetting, and electronic properties of metal clusters adsorbed on carbon nanotubes ». Journal of Applied Physics 104, n^o 1 (juillet 2008) : 013509. http://dx.doi.org/10.1063/1.2949691.

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Catara, F., Ph Chomaz et N. Giai. « Electronic properties of large metal clusters in jellium and pseudo-jellium models ». Zeitschrift f�r Physik D Atoms, Molecules and Clusters 33, n^o 3 (septembre 1995) : 219–27. http://dx.doi.org/10.1007/bf01437314.

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Öğüt, Serdar, Juan C. Idrobo, Julius Jellinek et Jinlan Wang. « Structural, Electronic, and Optical Properties of Noble Metal Clusters from First Principles ». Journal of Cluster Science 17, n^o 4 (19 octobre 2006) : 609–26. http://dx.doi.org/10.1007/s10876-006-0075-8.

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35

Garcia, M. E., G. M. Pastor et K. H. Bennemann. « Calculation of the electronic properties of neutral and ionized divalent-metal clusters ». Zeitschrift f�r Physik D Atoms, Molecules and Clusters 26, n^o 1-4 (mars 1993) : 293–95. http://dx.doi.org/10.1007/bf01429173.

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Meiwes-Broer, K. H. « Electronic properties of free and supported metal clusters studied by photoelectron spectroscopy ». Applied Physics A Solids and Surfaces 55, n^o 5 (novembre 1992) : 430–41. http://dx.doi.org/10.1007/bf00348330.

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Xia, Xinxin, Xiaoyu Kuang, Cheng Lu, Yuanyuan Jin, Xiaodong Xing, Gabriel Merino et Andreas Hermann. « Deciphering the Structural Evolution and Electronic Properties of Magnesium Clusters : An Aromatic Homonuclear Metal Mg17 Cluster ». Journal of Physical Chemistry A 120, n^o 40 (20 septembre 2016) : 7947–54. http://dx.doi.org/10.1021/acs.jpca.6b07322.

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Fang, Zhi Gang, Hong Yan Ban, Yun Gao et Ting Ting Gu. « DFT Study on Clusters Ni_4-xFe_xP (x=0~4) : A Theoretical Investigation on the Property of Amorphous Alloy Ni_80-xFe_xP₂₀ ». Advanced Materials Research 602-604 (décembre 2012) : 635–39. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.635.

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More than a hundred models of clusters Ni4-xFexP (x=0~4) have been designed and computed in duplicate and fourfold state on density function theory (DFT) to simulate amorphous alloys Ni80-xFexP20 that were the most familiar proportions in Ni-Fe-P amorphous system. The geometry, energy, electronic and catalytic properties have been discussed. The results disclosed that clusters could reflect some characteristic properties of binary amorphous alloys. And the clusters could predict the geometry and electron properties of corresponding ternary amorphous alloys. The addition of third element could enhance the system stability of Ni-P amorphous alloys. The metal atoms are the electrons gainers and metalloid atoms are the electrons offers in the clusters, and the ability of gaining electrons of atoms Ni is better than the one of atoms Fe. The trend of cluster Ni2Fe2P forming may be the keenest in clusters. It also would offer more excellent catalytic activity basing on Fermi level and density of state.

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Chauhan, Vikas, Arthur C. Reber et Shiv N. Khanna. « Metal Chalcogenide Clusters with Closed Electronic Shells and the Electronic Properties of Alkalis and Halogens ». Journal of the American Chemical Society 139, n^o 5 (26 janvier 2017) : 1871–77. http://dx.doi.org/10.1021/jacs.6b09416.

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Huu, Tho, et Tam Nguyen Minh. « A theoretical study of the first-row transition metal doped germanium clusters Ge14M ». Journal of Military Science and Technology 87 (25 mai 2023) : 50–58. http://dx.doi.org/10.54939/1859-1043.j.mst.87.2023.50-58.

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Geometry, stability, electronic structure, and magnetic properties of Ge14M clusters with M being a 3d transition metal atom, from Sc to Zn, were studied using density functional theory (DFT) calculations at B3PW91/6-311+G(d) level. The obtained results found that Ge14M clusters preferentially exist in its lowest possible spin state, except for M being Fe and Cr. The thermodynamic stability of the structures has been evaluated through the average binding and embedded energies. Ge14Ti and Ge14V clusters are considered to be the most stable in the Ge14M series (M = Sc - Zn) with the geometry of the C2 point group where M is located in the center of the Ge12 hexagonal prism along with two Ge-atoms capping on two Ge6 faces. In this series Ge14M clusters, only Ge14Fe cluster is stable at the high spin state, with a magnetic moment of 2mB.

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Skipetrov E.P., Bogdanov E.V., Skipetrova L.A., Solovev A.A. et Knotko A.V. « Magnetic properties of Pb-=SUB=-1-y-=/SUB=-Sc-=SUB=-y-=/SUB=-Te alloys ». Semiconductors 55, n^o 14 (2022) : 2131. http://dx.doi.org/10.21883/sc.2022.14.53858.9723.

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The magnetic field dependences of the magnetization (B≤9 T, T=2-70 K) of the samples from a single crystal Pb1-yScyTe (y=0.01) ingot, synthesized by the Bridgman method, are studied. It is established that, in accordance with the generally accepted model of the rearrangement of the electronic structure of alloys during doping, there is no paramagnetic contribution of single scandium ions located in the nodes of the metal sublattice in the studied samples. The magnetization of the samples contains several contributions: superparamagnetism of scandium clusters, linear in field diamagnetism of the crystal lattice and the paramagnetism of free electrons, as well as the oscillating contribution of the de Haas--van Alphen effect. The field dependences of the main contribution of scandium clusters are successfully approximated using the Langevin function. The average concentration, magnetic moment and the total magnetic moment of the clusters per unit volume of the sample were determined with an increase in the impurity concentration along the ingot. Keywords: PbTe-based alloys, 3d-transition metal impurities, rearrangement of electronic structure, field dependences of magnetization, superparamagnetism of scandium clusters.

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Fan, X., E. C. Dickey et S. J. Pennycook. « Z-Contrast Imaging and EELS Analysis of Chromium Doped Diamond-Like Carbon ». Microscopy and Microanalysis 5, S2 (août 1999) : 650–51. http://dx.doi.org/10.1017/s1431927600016573.

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Diamond-like carbon (DLC) has attracted considerable interest with a variety of potential applications [1]. A new class of amorphous films has been produced recently by incorporating metals within the carbon network. The electrical conductivity of these films varies a wide range, however nonlinear with the metal concentration. It is believed it is because metals may form clusters. Such nano-phase metal cluster encapsulated by an inert matrix can offer interesting applications, for example as nano-electrodes used in electrochemistry[2]. It is therefore fundamentally important to observe the metal cluster formation. By using Z-contrast imaging [3], the metal distribution can be directly determined on the atomic level. The local metal concentration and other electronic properties cafi also be analyzed by spatial resolved electron energy loss spectroscopy (EELS)

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Vernis, Laurence, Nadine El Banna, Dorothée Baïlle, Elie Hatem, Amélie Heneman et Meng-Er Huang. « Fe-S Clusters Emerging as Targets of Therapeutic Drugs ». Oxidative Medicine and Cellular Longevity 2017 (2017) : 1–12. http://dx.doi.org/10.1155/2017/3647657.

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Fe-S centers exhibit strong electronic plasticity, which is of importance for insuring fine redox tuning of protein biological properties. In accordance, Fe-S clusters are also highly sensitive to oxidation and can be very easily alteredin vivoby different drugs, either directly or indirectly due to catabolic by-products, such as nitric oxide species (NOS) or reactive oxygen species (ROS). In case of metal ions, Fe-S cluster alteration might be the result of metal liganding to the coordinating sulfur atoms, as suggested for copper. Several drugs presented through this review are either capable of direct interaction with Fe-S clusters or of secondary Fe-S clusters alteration following ROS or NOS production. Reactions leading to Fe-S cluster disruption are also reported. Due to the recent interest and progress in Fe-S biology, it is very likely that an increasing number of drugs already used in clinics will emerge as molecules interfering with Fe-S centers in the near future. Targeting Fe-S centers could also become a promising strategy for drug development.

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Chauhan, Vikas, Akansha Singh, Chiranjib Majumder et Prasenjit Sen. « Structural, electronic and magnetic properties of binary transition metal aluminum clusters : absence of electronic shell structure ». Journal of Physics : Condensed Matter 26, n^o 1 (25 novembre 2013) : 015006. http://dx.doi.org/10.1088/0953-8984/26/1/015006.

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Sharma, Shailendra K., Bernt Johannessen, Vladimir B. Golovko et Aaron T. Marshall. « X-ray Absorption Spectroscopy of Phosphine-Capped Au Clusters ». Inorganics 11, n^o 5 (28 avril 2023) : 191. http://dx.doi.org/10.3390/inorganics11050191.

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The structural determination of ultrasmall clusters remains a challenge due to difficulties in crystallisation. Often the atomically precise clusters undergo structural change under the influence of the environment. X-ray absorption spectroscopy (XAS) can be an attractive tool to study the electronic and geometric properties of such clusters deposited onto various supports under in situ conditions. Herein, [Au6(dppp)4](NO3)2, [Au9(PPh3)8](NO3)3, [Au13(dppe)5Cl2]Cl3, and Au101(PPPh3)21Cl5 clusters were studied using XAS. The clusters exhibited distinct features compared to bulk gold. XANES results show a systematic increase in the absorption edge energy and white line intensity, with a decrease in cluster nuclearity. The EXAFS of clusters are sensitive to nuclearity and ligands and were fitted with their known crystal structures. This study advances the understanding of the phosphine-ligated metal clusters relevant to practical applications in catalysis and sensing.

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Chen, Yao, et Shengqian Ma. « Microporous lanthanide metal-organic frameworks ». Reviews in Inorganic Chemistry 32, n^o 2-4 (1 décembre 2012) : 81–100. http://dx.doi.org/10.1515/revic-2012-0003.

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AbstractMicroporous metal-organic frameworks (MOFs) based on lanthanide metal ions or clusters represent a group of porous materials, featuring interesting coordination, electronic, and optical properties. These attractive properties in combination with the porosity make microporous lanthanide MOFs (Ln-MOFs) hold the promise for various applications. This review is to provide an overview of the current status of the research in microporous Ln-MOFs, and highlight their potential as types of multifunctional materials for applications in gas/solvent adsorption and separation, luminescence and chemical sensing and catalysis.

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Molina Tenrreyra, Uriel Omar, Rodrigo Hebert Mojica Molina et Ana Elizabeth Torres Hernández. « Au-Ru nanoparticles in catalysis, analysis from first-principles calculations ». Mundo Nano. Revista Interdisciplinaria en Nanociencias y Nanotecnología 15, n^o 29 (7 février 2022) : 1e—21e. http://dx.doi.org/10.22201/ceiich.24485691e.2022.29.69700.

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Nobel-metal based bimetallic nanoparticles (BNPs) are composed of two different metals presenting heteroatom interactions. In these nanomaterials it is possible to tune the relative composition that allows for the modulation of electronic and catalytic properties. They are of great interest for their technological and industrial applications due to their catalytic properties which may exceed those of their monometallic analogue structures. A theoretical perspective on the electronic, stability and reactivity related properties of gold, ruthenium and Au-Ru nanoparticles is presented herein. This analysis considered the use of first-principles methods and the cluster approach to get a physical insight into the novel properties that arise from the combination of two metals in the nano and sub-nano scale. Au-Ru BNPs may present a higher catalytic efficiency than the monometallic structures due to the synergy between the metals in the CO oxidation reaction. However, the effect of Ru over the Au-based NPs on their enhanced catalytic activity is not well understood. A density functional theory (DFT) study of one Au-Ru cluster model was performed to analyze its electronic properties and to gain a better understanding in the stability of structures with various metal compositions. Based on the computed mixing enthalpy, the Au-Ru cluster with a core-shell type morphology and a relative composition close to 1:0.75 was determined as the most stable one. Finally, a CO oxidation reaction pathway different from that determined for Au-NPs was presented for the free particle occurring in the Au-Ru interface. O2 may undergo adsorption on a Ru site through a dissociative process. The computed CO oxidation barrier height is lower than that found for the monometallic Ru clusters but is higher than that determined for Au clusters. This study will guide further research on this kind of model nanostructures in heterogeneous catalysis.

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Chen, Junchi, Lingfang Liu, Haile Liu, Yonghui Li, Junying Wang, Xiaoyu Mu, Fujuan Xu, Tianyu Liu et Xiao-Dong Zhang. « Ultrabright bimetallic AuAg complex : From luminescence mechanism to biological application ». Journal of Innovative Optical Health Sciences 13, n^o 05 (27 juin 2020) : 2041001. http://dx.doi.org/10.1142/s1793545820410011.

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Metal clusters have attracted wide interests due to their unique electronic and optical properties, but the low luminescence quantum yield (QY) prevents them from potential biomedical applications. In this work, silver-doped Au nanoclusters (NCs) are shown to be able to improve the QY of metal clusters. We succeeded in synthesizing ultrabright glutathione (GSH) protected AuAg clusters with 10.8% QY by a one-pot route. Their florescence is about 7.5 times brighter than pure Au NCs, with super photostability and good biocompatibility in physiological environment. Based on density functional theory (DFT) calculations, we investigated the electronic structures and optical properties of the AuAg NCs. The results show that the increase of the density of states of the lowest unoccupied molecular orbital (LUMO) leads to the fluorescence enhancement. In addition, two-photon excitation fluorescence imaging has been performed to show their great potential for biomedicine.

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Pope, Edward J. A., et J. D. Mackenzie. « Ultrafine Metal Particles in Porous and Dense Silica Gels ». MRS Bulletin 13, n^o 3 (mars 1988) : 20–23. http://dx.doi.org/10.1557/s0883769400066100.

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The present trend of developing electronic devices with increasingly fine dimensions borders on a number of fundamental scientific questions about the very nature of how materials at ultrafine dimensions behave. This article addresses some of these questions. The fabrication of discrete metallic phases in porous and nonporous glassy matrices presents a number of exciting device possibilities. Methods of fabricating ultrafine metallic phases in silica via the sol-gel route are presented.In attempting to fabricate materials with ultrafine physical dimensions for a wide variety of applications, several fundamental questions arise about the nature of materials behavior. For example, how many metal atoms are necessary to form a cluster exhibiting “metallic“ properties? Moreover, does the number of atoms necessary depend upon which metallic property is examined? This question has been partly addressed by D.C. Johnson and co-workers with regard to magnetism in osmium clusters. Their results show a threefold increase in magnetic susceptibility between clusters containing 3–10 osmium atoms.Another important question, especially when considering device applications, is how the relative contributions of surface and bulk thermodynamics affect such properties as phase transformations. In addition, ultrafine phase dimensions interact with the fundamental unit lengths of a wide range of processes, including the wavelength of visible light, the mean free path lengths of conduction processes, the wavelengths of phonon vibrations, etc. How do these interactions affect optical, thermal, and electronic properties?Fabrication of ultrafine metallic particles in porous and nonporous matrices may lead to many possible device applications including heterogeneous catalysts, nonlinear optic devices, highvoltage switching devices based on interparticle tunneling, and perhaps even new types of charge storage devices (capacitors).

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Koblova, Elena, Alexander Yu Ustinov et Oleg Shcheka. « Theoretical Study of Copper (II) Oxide Clusters and their Interaction with CO ». Applied Mechanics and Materials 709 (décembre 2014) : 358–63. http://dx.doi.org/10.4028/www.scientific.net/amm.709.358.

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Copper (II) oxide clusters (CuO)nwith n = 1 – 4, 6 have been calculated by DFT method with the exchange-correlation functional B3LYP. The structural, energy and electronic properties have been studied. Much attention was given to the interaction between CO and active centers of the clusters. The most probable orientation of CO on the metal oxide surface has been determined and the stability of clusters has been evaluated.

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