Articles de revues : « Functional Gold Clusters »

1

Ferrari, Piero, et Klavs Hansen. « Computing gold cluster energies with density functional theory : the importance of correlation ». Physical Chemistry Chemical Physics 23, n^o 27 (2021) : 14830–35. http://dx.doi.org/10.1039/d1cp02084f.

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Calculating energy-dependent properties on gold clusters via density functional theory depend critically on the choice of functional. Here we use measured dissociation energies as benchmark data for testing the performance of different functionals.

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Allen, Darnel J., Wayne E. Archibald, John A. Harper, John C. Saputo et Daniel Torres. « Density Functional Investigation of the Inclusion of Gold Clusters on a CH3S Self-Assembled Lattice on Au(111) ». Advances in Chemistry 2016 (17 octobre 2016) : 1–8. http://dx.doi.org/10.1155/2016/6080343.

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We employ first-principles density functional theoretical calculations to address the inclusion of gold (Au) clusters in a well-packed CH3S self-assembled lattice. We compute CH3S adsorption energies to quantify the energetic stability of the self-assembly and gold adsorption and dissolution energies to characterize the structural stability of a series of Au clusters adsorbed at the SAM-Au interface. Our results indicate that the inclusion of Au clusters with less than four Au atoms in the SAM-Au interface enhances the binding of CH3S species. In contrast, larger Au clusters destabilize the self-assembly. We attribute this effect to the low-coordinated gold atoms in the cluster. For small clusters, these low-coordinated sites have significantly different electronic properties compared to larger islands, which makes the binding with the self-assembly energetically more favorable. Our results further indicate that Au clusters in the SAM-Au interface are thermodynamically unstable and they will tend to dissolve, producing Au adatoms incorporated in the self-assembly in the form of CH3S-Au-SCH3 species. This is due to the strong S-Au bond which stabilizes single Au adatoms in the self-assembly. Our results provide solid insight into the impact of adatom islands at the CH3S-Au interface.

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Priyanka, Sumali Bansal et Keya Dharamvir. « Structure of Small Gold Clusters with Si Doping Using DFT (Au_nSi, n=1-10, 19) ». Journal of Nano Research 24 (septembre 2013) : 203–12. http://dx.doi.org/10.4028/www.scientific.net/jnanor.24.203.

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The structures of silicon doped gold clusters AunSi (n = 1-10 and 19) have been investigated using first principle calculations based on density functional theory (DFT). Calculations indicate that the stability of a gold cluster increases with the introduction of a Si atom. In all the low lying geometries, Si prefers peripheral positions. For every ground state configuration with n > 3 (n = 6 and 9 being exceptions) Si has tetra-coordination. In almost all of the tetra coordinated geometries the coordination unit including Si, is in the form of a square pyramid with gold atoms forming the square base. Electronic properties such as HOMO-LUMO gap, ionization potential and electron affinity have also been calculated and support the relative stability of clusters with even n. The study of Au20 cage doped with Si atom has been done .Similar to smaller Si doped gold clusters; the Si atom prefers an exohedral position. The doping of Si atom has enhanced the stability and chemical reactivity of Au20 cluster.

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Alamanova, Denitsa, Yi Dong, Habib ur Rehman, Michael Springborg et Valeri G. Grigoryan. « Structural and Electronic Properties of Gold Clusters ». Computing Letters 1, n^o 4 (6 mars 2005) : 319–30. http://dx.doi.org/10.1163/157404005776611394.

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We study the structure and energetics of AuN clusters by means of parameterfree density-functional calculations (N ≤ 8), jellium calculations (N ≤ 60), embeddedatom calculations (N ≤ 150), and parameterized density-functional calculations (N ≤ 40) in combination with different methods for determining the structure of the lowest total energy. By comparing the results from the different approaches, effects due to geometric packing and those due to the electronic orbitals can be identified. Different descriptors that highlight the results of the analysis are presented and used.

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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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Vuong, Van Quan, Jenica Marie L. Madridejos, Bálint Aradi, Bobby G. Sumpter, Gregory F. Metha et Stephan Irle. « Density-functional tight-binding for phosphine-stabilized nanoscale gold clusters ». Chemical Science 11, n^o 48 (2020) : 13113–28. http://dx.doi.org/10.1039/d0sc04514d.

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We report a parameterization of the density-functional tight-binding (DFTB) method for the accurate prediction of molecular, electronic and vibrational structure of phosphine-ligated nanoscale gold clusters, metalloids, and gold surfaces.

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Shi, Yong, Cuihua Zhao, Xing Chen, Cuiting Chen, Xi Zhou et Jianhua Chen. « DFT study on the electronic structure and optical properties of an Au-deposited α-Fe₂O₃ (001) surface ». RSC Advances 12, n^o 9 (2022) : 5447–57. http://dx.doi.org/10.1039/d1ra07933f.

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The electronic structure and optical properties of gold clusters deposited on an α-Fe2O3 surface were studied by using density functional theory (DFT), with a special emphasis on the influence of Au cluster sizes.

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Zhao, Shuang, YunLi Ren, YunLai Ren, JianJi Wang et WeiPing Yin. « Density Functional Study of Hydrogen Binding on Gold and Silver−Gold Clusters ». Journal of Physical Chemistry A 114, n^o 14 (15 avril 2010) : 4917–23. http://dx.doi.org/10.1021/jp910230p.

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Chen, Yuheng. « Biosensors Based on Gold Nano-Clusters ». Theoretical and Natural Science 4, n^o 1 (28 avril 2023) : 110–18. http://dx.doi.org/10.54254/2753-8818/4/20220531.

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The world is entering an era of strong infectious diseases, and it is urgent to develop a new type of rapid, efficient detection system. This graph specifically illustrates the detection function of the gold nanoparticles, and the gold nanoparticles-based sensor. Gold-based nanoclusters (NCs) which has a small particle size, has a high degree of stability and no impact on the biological activity. Gold-based NCs has a surface plasma resonance effect and produces visible color, which can be detected by observing the color change using the agglomeration reaction of the detected substance with Gold-based NCs. In order to specifically detect certain biomolecules, some functional groups or small DNA molecular chains of nanolodin are usually modified on it to have a selective detection capability. In the review, we introduce a total of four nano-gold applications, for bacteria, viruses, DNA and cancer, also, respectively elaborating some recent Gold-based NCs detection applications.

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Lang, Sandra M., Thorsten M. Bernhardt, Joost M. Bakker, Bokwon Yoon et Uzi Landman. « Methanol C–O Bond Activation by Free Gold Clusters Probed via Infrared Photodissociation Spectroscopy ». Zeitschrift für Physikalische Chemie 233, n^o 6 (26 juin 2019) : 865–80. http://dx.doi.org/10.1515/zpch-2018-1368.

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Abstract The activation of methanol (CD3OD and CD3OH) by small cationic gold clusters has been investigated via infrared multiphoton dissociation (IR-MPD) spectroscopy in the 615–1760 cm−1 frequency range. The C–O stretch mode around 925 cm−1 and a coupled CD3 deformation/C–O stretch mode around 1085 cm−1 are identified to be sensitive to the interaction between methanol and the gold clusters, whereas all other modes in the investigated spectral region remain unaffected. Based on the spectral shift of these modes, the largest C–O bond activation is observed for the mono-gold Au(CD3OD)+ cluster. This activation decreases with increasing the cluster size (number of gold atoms) and the number of adsorbed methanol molecules. Supporting density functional theory (DFT) calculations reveal that the C–O bond activation is caused by a methanol to gold charge donation, whereas the C–D and O–D bonds are not significantly activated by this process. The results are discussed with respect to previous experimental and theoretical investigations of neutral and cationic gold-methanol complexes focusing on the C–O stretch mode.

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Saxena, Shivi, et Ramakrishna Guda. « (Digital Presentation) Fabrication of Monolayer-Protected Gold Cluster Thin Films : Electrochemical and Optical Properties ». ECS Meeting Abstracts MA2022-01, n^o 20 (7 juillet 2022) : 1103. http://dx.doi.org/10.1149/ma2022-01201103mtgabs.

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Quantum-sized monolayer-protected gold clusters have captivated the imagination of scientists over the last two decades and show exciting optical, electrochemical and catalytic properties when compared to larger-sized plasmonic gold nanoparticles, making them useful for myriad new applications in photonics, catalysis and sensors. One interesting property is the photoluminescence (PL) of gold clusters making them suitable as biological imaging labels. However, the low PL Quantum Yields (QY) are a concern for these clusters and research is focused on improving the PL QYs. One strategy, our research group has worked on is the shell-gold rigidification via the use of surfactants and proteins. Shell ligand rigidification was achieved by ion pairing with bulky tertiary alkyl ammonium groups and aromatic chromophores. Another strategy to reduce the non-radiative deactivation pathways is by making the gold cluster thin films. In a recent study, it was shown that solid state films of clusters not only have manifold increase in PL quantum yield but also their luminescent lifetimes and two photon absorption cross-sections are greatly enhanced in comparison to their solution analogues. Researchers have worked on various strategies to make gold cluster thin films for device applications. One problem with thin films of gold clusters is that the clusters lose their interesting optical and electrochemical properties that were observed in solution phase. For making the clusters useful by enhancing PL for photonic device applications, it is important for the clusters to retain their properties in solid state, which is the main objective of the study carried out here. One problem is that drying intrinsic gold clusters results in crystallization whose optical properties are difficult to characterize. In this study, we have used Nafion and polyvinylpyrrolidone (PVP) to make thin films of water-soluble glutathione-protected gold clusters. Water soluble cluster Au22(SG)18 with reported PLQY of 8% were synthesized and characterized by UV-VIS absorption and PL measurements and thin films of these clusters were made using water soluble PVP and Nafion polymers via drop casting. Enhanced PL and electrochemical properties were observed for clusters in solid state. Similarly, non-polar gold cluster films are fabricated with Polystyrene and optical absorption and PL properties were retained in the solid state. Although drop casting with polymers was found to retain the optical properties, the uniformity of films is a problem. The uniformity of the film is dependent on solvent’s surface tension thus diminishing the quality of the film. Therefore, there is a need of depositing films of gold clusters in a controlled manner which governs their thickness and uniformity. Electropolymerization technique is known to make films during the polymerization of monomers possessing functional groups whose oxidation or reduction via anti-bonding or non-boding electrons on a heteroatom. In this study, we have used electropolymerization strategy to fabricate thin films of gold clusters on conducting substrates. The film is deposited at the working electrode during cyclic voltammetric (CV) sweep when passed through the required reduction or oxidation potential of the monomer under suitable conditions. This technique makes a uniform film throughout the exposed area of the working electrode active surface and the thickness of the film is often proportional to the number of sweep cycles employed. Therefore, introduction of gold clusters in this process with monomers which are previously known to bond with each other will incorporate clusters in the film during the polymerization process and will ease their film formation with uniform thickness. Amongst various size gold clusters, the one which shows good stability as a result of following the magic number series is Au25(SR)18 - . The stability of clustersis one of the important parameter required for practical applications. Aniline and other amine based monomers are used as precursors to make thin films of Au25 on conducting substrate such as Indium tin oxide. By solubilizing the gold clusters with the monomers they are deposited along with the polymers.

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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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Ferrari, Piero, et Ewald Janssens. « Relative Stability of Small Silver, Platinum, and Palladium Doped Gold Cluster Cations ». Applied Sciences 9, n^o 8 (23 avril 2019) : 1666. http://dx.doi.org/10.3390/app9081666.

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The stability patterns of single silver, platinum, and palladium atom doped gold cluster cations, MAuN−1+ (M = Ag, Pt, Pd; N = 3–6), are investigated by a combination of photofragmentation experiments and density functional theory calculations. The mass spectra of the photofragmented clusters reveal an odd-even pattern in the abundances of AgAuN−1+, with local maxima for clusters containing an even number of valence electrons, similarly to pure AuN+. The odd-even pattern, however, disappears upon Pt and Pd doping. Computed dissociation energies agree well with the experimental findings for the different doped clusters. The effect of Ag, Pt, and Pd doping is discussed on the basis of an analysis of the density of states of the N = 3–5 clusters. Whereas Ag delocalizes its 5s valence electron in all sizes, this process is size-specific for Pt and Pd.

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Ferrari, Piero, et Ewald Janssens. « Argon Adsorption on Cationic Gold Clusters Aun+ (n ≤ 20) ». Molecules 26, n^o 13 (4 juillet 2021) : 4082. http://dx.doi.org/10.3390/molecules26134082.

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The interaction of Aun+ (n ≤ 20) clusters with Ar is investigated by combining mass spectrometric experiments and density functional theory calculations. We show that the inert Ar atom forms relatively strong bonds with Aun+. The strength of the bond strongly varies with the cluster size and is governed by a fine interplay between geometry and electronic structure. The chemical bond between Aun+ and Ar involves electron transfer from Ar to Au, and a stronger interaction is found when the Au adsorption site has a higher positive partial charge, which depends on the cluster geometry. Au15+ is a peculiar cluster size, which stands out for its much stronger interaction with Ar than its neighbors, signaled by a higher abundance in mass spectra and a larger Ar adsorption energy. This is shown to be a consequence of a low-coordinated Au adsorption site in Au15+, which possesses a large positive partial charge.

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Koskinen, P., H. Häkkinen, G. Seifert, S. Sanna, Th Frauenheim et M. Moseler. « Density-functional based tight-binding study of small gold clusters ». New Journal of Physics 8 (30 janvier 2006) : 9. http://dx.doi.org/10.1088/1367-2630/8/1/009.

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Krüger, Sven, Mauro Stener et Notker Rösch. « Relativistic density functional study of gold coated magnetic nickel clusters ». Journal of Chemical Physics 114, n^o 12 (22 mars 2001) : 5207–15. http://dx.doi.org/10.1063/1.1349058.

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H�berlen, Oliver D., Sai-Cheong Chung, Notker R�sch et Notker R�sch. « Relativistic density-functional studies of naked and ligated gold clusters ». International Journal of Quantum Chemistry 52, S28 (12 février 1994) : 595–610. http://dx.doi.org/10.1002/qua.560520853.

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Qi, Bin, Chenchen Wu, Xin Li, Dan Wang, Liang Sun, Bo Chen, Wenjing Liu, Haibo Zhang et Xiaohai Zhou. « Self-Assembled Magnetic Gold Catalysts from Dual-Functional Boron Clusters ». ChemCatChem 10, n^o 10 (9 mai 2018) : 2285–90. http://dx.doi.org/10.1002/cctc.201702011.

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Zhou, Zhi-Jian, et Yan-Fei Hu. « Structures, Stabilities, and Electronic Properties of Gold Silicide Clusters : Comparison with Pure Silicon Clusters ». Zeitschrift für Naturforschung A 67, n^o 1-2 (1 février 2012) : 99–110. http://dx.doi.org/10.5560/zna.2011-0061.

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The local meta-GGA (generalized gradient approximation) exchange correlation density functional (TPSS) with relativistic effective core potential was employed to systematically investigate the geometric structures, stabilities, and electronic properties of bimetallic Au2Sin (n = 1 - 8) clusters. The optimized geometries show that the most stable isomers have a three-dimensional structure except for Au2Si1,3 clusters. The doped gold atoms prefer to occupy the surface site in the Au2Sin clusters. Here, the averaged atomic binding energies and fragmentation energies show that the Au2Si5 isomer is the most stable among the Au2Sin (n = 1 - 8) clusters. A pronounced even-odd alternation is found in the energy difference between the highest occupied and the lowest unoccupied molecular orbital (HOMO-LUMO gaps), especially, the Au2Si5 cluster has the largest HOMO-LUMO gap of 2.06 eV. Moreover, the reverse even-odd alternation rule to the average polarizability per atom versus the charges transfer was found. A transition point appears at n = 5.

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Zhao, Ya-Ru. « Structures, Stabilities, and Electronic Properties for Rare-Earth Lanthanum Doped Gold Clusters ». Zeitschrift für Naturforschung A 70, n^o 2 (1 février 2015) : 91–99. http://dx.doi.org/10.1515/zna-2014-0160.

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AbstractThe structures, stabilities, and electronic properties of rare-earth lanthanum doped gold La2Aun (n = 1–9) and pure gold Aun (n ≤ 11) clusters have been investigated by using density functional theory. The optimized geometries show that the lowest energy structures of La2Aun clusters favour the 3D structure at n ≥ 3. The lanthanum atoms can strongly enhance the stabilities of gold clusters and tend to occupy the most highly coordinated position. By analysing the gap, vertical ionization potential, and chemical hardness, it is found that the La2Au6 isomer possesses higher stability for small-sized La2Aun clusters (n = 1–9). The charges in the La2Aun clusters transfer from La atoms to the Aun host. In addition, Wiberg bond indices analysis reveals that the intensity of different bonds of La2Aun clusters exhibits a sequence of La–La bond > La-Au bond > Au–Au bond.

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Ding, Li-Ping, Xiao-Yu Kuang, Peng Shao, Ming-Min Zhong et Yan-Fang Li. « Structural and Electronic Properties of Stable AunIr2 (n = 1 – 7) Clusters : Comparison with Pure Gold Clusters ». Zeitschrift für Naturforschung A 67, n^o 12 (1 décembre 2012) : 729–38. http://dx.doi.org/10.5560/zna.2012-0086.

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The geometrical structures, relative stabilities, electronic and magnetic properties of AunIr2 (n = 1 - 7) clusters have been systematically investigated by using meta-generalized gradient approximation (meta-GGA) Tao-Perdew-Staroverov-Scuseria (TPSS) functional in comparison with pure gold clusters. The optimized geometries show that the two doping iridium atoms can affect the structure of the host cluster. Compared with the pure Aun+2 clusters, the lowest energy AunIr2 (n=1 - 7) clusters favour higher spin multiplicity except for Au7Ir2. Furthermore, the calculated binding energies, fragmentation energies, second-order difference energies, and the highest occupied-lowest unoccupied energy gaps indicate that the stability of AunIr2 is enhanced. Natural population analysis reveals that the charges transfer from the Aun frames to the iridium atoms for Au3;4;6;7Ir2 clusters. In addition, charges and magnetic moments of 6s, 5d, and 6p states for the iridium atoms in AunIr2 (n = 1 - 7) clusters are also analyzed and compared.

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Bonačić-Koutecký, Vlasta, Jaroslav Burda, Roland Mitrić, Maofa Ge, Giuseppe Zampella et Piercarlo Fantucci. « Density functional study of structural and electronic properties of bimetallic silver–gold clusters : Comparison with pure gold and silver clusters ». Journal of Chemical Physics 117, n^o 7 (15 août 2002) : 3120–31. http://dx.doi.org/10.1063/1.1492800.

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Hua-Ping, Mao, Wang Hong-Yan et Sheng Yong. « Density functional study on structural and electronic properties of bimetallic gold–yttrium clusters : comparison with pure gold and yttrium clusters ». Chinese Physics B 17, n^o 6 (juin 2008) : 2110–15. http://dx.doi.org/10.1088/1674-1056/17/6/028.

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Wang, Huai-Qian, Xiao-Yu Kuang et Hui-Fang Li. « Density functional study of structural and electronic properties of bimetallic copper–gold clusters : comparison with pure and doped gold clusters ». Physical Chemistry Chemical Physics 12, n^o 19 (2010) : 5156. http://dx.doi.org/10.1039/b923003c.

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Ranjan, Prabhat, et Tanmoy Chakraborty. « A DFT Study of Vanadium Doped Gold Nanoalloy Clusters ». Key Engineering Materials 777 (août 2018) : 183–89. http://dx.doi.org/10.4028/www.scientific.net/kem.777.183.

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The electronic and optical properties of AunV (n=1-8) nanoalloy clusters have been investigated invoking Density Functional Theory (DFT) based descriptors. Conceptual DFT based global descriptors have been used to exhibit experimental properties qualitatively. In this report, the experimental properties of AunV (n=1-8) nanoalloy clusters are correlated in terms of DFT based descriptors viz., HOMO-LUMO energy gap, Hardness, Softness, Electronegativity, Electrophilicity Index and Dipole Moment. The doping of single vanadium atom in gold clusters enhances the stability of gold clusters and also display pronounced odd-even oscillation behaviors. The computed bond length of instant clusters are numerically close with experimental data. The linear regression analysis has been done in terms of correlation between our computed descriptors and their experimental counterparts.

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Deka, Ajanta. « Structure and Reverse Hydrogen Spillover in Mononuclear Au0 and AuI Complexes Bonded to Faujasite Zeolite : A Density Functional Study ». Journal of Catalysts 2013 (25 mai 2013) : 1–5. http://dx.doi.org/10.1155/2013/467846.

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We have studied the structure of mononuclear gold supported on acidic form of faujasite zeolite in two oxidation states, namely, 0 and +1, using density functional theory. The binding of the gold monomer to the zeolite support is stronger in the oxidation state +1 than in the oxidation state 0. For the oxidation state 0, the hydrogenated clusters AuH/(2H)-FAU, AuH2/H-FAU generated by stepwise reverse hydrogen spillover from bridging OH groups of zeolite are energetically preferred over the Au/(3H)-FAU structure. Reverse hydrogen spillover of all the three acidic protons from the zeolite to the Au monomer did not lead to a stable structure. The calculated reverse hydrogen spillover energy per hydrogen atom for zeolite supported AuH and AuH2 clusters are −10.2 and −5.1 kJ/mol, respectively, in the oxidation state 0, while in the oxidation state +1 it is 20.9 kJ/mol for zeolite supported Au+H cluster.

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Bas, B. Soulé de, M. J. Ford et M. B. Cortie. « Melting in small gold clusters : a density functional molecular dynamics study ». Journal of Physics : Condensed Matter 18, n^o 1 (9 décembre 2005) : 55–74. http://dx.doi.org/10.1088/0953-8984/18/1/004.

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Sun Lu-Shi, Zhang An-Chao, Xiang Jun, Guo Pei-Hong, Liu Zhi-Chao et Su Sheng. « Density functional study of interation of Hg with small gold clusters ». Acta Physica Sinica 60, n^o 7 (2011) : 073103. http://dx.doi.org/10.7498/aps.60.073103.

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Zhang, Shuai, Yu Zhang, Xing Qiang Yang, Gen Quan Li et Zhi Wen Lu. « Probing the structures and electronic properties of anionic and neutral BiAun−1,0 (n = 2–20) clusters : a pyramid-like BiAu13 cluster ». New Journal of Chemistry 43, n^o 25 (2019) : 10030–37. http://dx.doi.org/10.1039/c9nj01821b.

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The geometric structures and electronic properties of bismuth-doped gold clusters, BiAu_n^−1,0 (n = 2–20), are studied via a combination of the Crystal structure AnaLYsis by Particle Swarm Optimization structure prediction software and the density functional theory approach.

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Kadioglu, Y., O. Üzengi Aktürk et M. Tomak. « Electronic and geometric structure of AuxCuy clusters studied by density functional theory ». International Journal of Modern Physics C 25, n^o 06 (23 avril 2014) : 1450011. http://dx.doi.org/10.1142/s0129183114500119.

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We have determined the stable structures of Au Cu n, Au 2 Cu n, Au 3 Cu n and Au x Cu 8-x clusters. It has been observed that Au Cu n, Au 2 Cu n and Au 3 Cu n systems have two-dimensional (2D) structures up to six atoms and they become three-dimensional (3D) afterwards. Au x Cu 8-x clusters favor 3D structures till the Au 7 Cu 1 cluster. We have found a lowest energy isomer of Au 6 Cu 2 from the literature. Bond lengths, binding energies, density of states (DOS), highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO-LUMO) gaps, ionization potential (IP) and electron affinity (EA) have been calculated for these structures using the first principles density functional theory (DFT) within the generalized gradient approximation (GGA) and the local density approximation (LDA). Generally, we have observed the overlap between s electrons of Cu and p electrons of Au near the Fermi level. Charge transfers are calculated by using the Löwdin analysis. It is observed that one Cu atom does not significantly modify the clusters which have more gold atoms. It is also seen that these clusters generally have nonmagnetic properties and results are consistent with the hybridization between s and d orbitals of Au in Au x Cu 8-x clusters.

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Aubert, Tangi, Nicolas Nerambourg, Chrystelle Neaime, Francisco Cabello-Hurtado, Marie Andrée Esnault, Dominique Lebret-Chauvel, Sylvie Jeanne et al. « Multi-Functional Silica Nanoparticles Based on Metal Atom Clusters : From Design to Toxicological Studies ». Key Engineering Materials 617 (juin 2014) : 179–83. http://dx.doi.org/10.4028/www.scientific.net/kem.617.179.

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We report on the interest of luminescent and nanosized metal atom clusters for the development of functional silica nanoparticles. Furthermore, multi-functional hybrid nanoparticles have been achieved by associating these luminescent clusters with magnetic γ-Fe2O3 nanocrystals and plasmonic gold nanocrystals. In addition, as part of the risk evaluation before potential applications, the toxicity of the nanoparticles was evaluated both on plants and on human cells.

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Nhat, Pham Vu, Nguyen Thanh Si, Nguyen Ngoc Khanh Anh, Long Van Duong et Minh Tho Nguyen. « The Au12 Gold Cluster : Preference for a Non-Planar Structure ». Symmetry 14, n^o 8 (11 août 2022) : 1665. http://dx.doi.org/10.3390/sym14081665.

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The transition point from a two-dimensional (2D) to a three-dimensional (3D) structure in a series of small gold clusters remains a topic of continuing debate. In the present study, coupled-cluster CCSD(T) and DFT calculations are performed to re-examine the relative energies of several low-lying isomers of Au12, aiming to shed new light on this issue. At odds with many previous reports on the preference of a planar di-capped elongated-hexagon structure, the Au12 size is found to energetically prefer a globular cup-like form with C2v symmetry. While DFT results are not able to assign the most stable form of Au12 as the relative energies between the lowest-lying isomers are strongly functional-dependent, coupled-cluster theory calculations point out the preference of a 3D structure for having a D3h symmetry. Such a prediction is further supported by a comparison of the vibrational spectra computed using the revTPSS density functional with the available experimental infrared ones that were previously recorded from the far-IR multiple photon dissociation (FIR-MPD) experiment.

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Morgenstern, Annika, Rico Thomas, Apoorva Sharma, Marcus Weber, Oleksandr Selyshchev, Ilya Milekhin, Doreen Dentel et al. « Deposition of Nanosized Amino Acid Functionalized Bismuth Oxido Clusters on Gold Surfaces ». Nanomaterials 12, n^o 11 (26 mai 2022) : 1815. http://dx.doi.org/10.3390/nano12111815.

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Bismuth compounds are of growing interest with regard to potential applications in catalysis, medicine, and electronics, for which their environmentally benign nature is one of the key factors. One thing that currently hampers the further development of bismuth oxido-based materials, however, is the often low solubility of the precursors, which makes targeted immobilisation on substrates challenging. We present an approach towards the solubilisation of bismuth oxido clusters by introducing an amino carboxylate as a functional group. For this purpose, the bismuth oxido cluster [Bi38O45(NO3)20(dmso)28](NO3)4·4dmso (dmso = dimethyl sulfoxide) was reacted with the sodium salt of tert-butyloxycabonyl (Boc)-protected phenylalanine (L-Phe) to obtain the soluble and chiral nanocluster [Bi38O45(Boc–Phe–O)24(dmso)9]. The exchange of the nitrates by the amino carboxylates was proven by nuclear magnetic resonance, Fourier-transform infrared spectroscopy, as well as elemental analysis and X-ray photoemission spectroscopy. The solubility of the bismuth oxido cluster in a protic as well as an aprotic polar organic solvent and the growth mode of the clusters upon spin, dip, and drop coating on gold surfaces were studied by a variety of microscopy, as well as spectroscopic techniques. In all cases, the bismuth oxido clusters form crystalline agglomerations with size, height, and distribution on the substrate that can be controlled by the choice of the solvent and of the deposition method.

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Chen, Yang-Mei, Xiao-Yu Kuang, Xiao-Wei Sheng, Huai-Qian Wang, Peng Shao et Min-Ming Zhong. « Investigation of Carbon Monoxide Adsorption on Cationic Gold- Palladium Clusters ». Zeitschrift für Naturforschung A 68, n^o 10-11 (1 novembre 2013) : 651–58. http://dx.doi.org/10.5560/zna.2013-0042.

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Density functional calculations have been performed for the carbon monoxide molecule adsorption on AunPd+m(n+m ≤ 6) clusters. In the process of CO adsorption, small Au clusters and Pd clusters tend to be an Au atom and three Pd atoms adsorption, respectively. For the mixed Au-Pd clusters, an Au atom, a Pd atom, two atoms consisted of an Au atom and a Pd atom, two Pd atoms, and three Pd atoms adsorption structures are displayed. The highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps and natural bond orbital charge population are calculated. Moreover, CO adsorption energy, CO stretching frequency, and CO bond length (upon adsorption) are also analysed in detail. The results predict that the adsorption strength of Au clusters with CO and the C-O vibration strength is enhanced and reduced after doping of Pd in the AunPdmCO+ complexes, respectively

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Tang, Cui-Ming, Xiao-Xu Chen et Xiang-Dong Yang. « Equilibrium geometries, electronic and magnetic properties of small AunNi- (n = 1-9) clusters ». International Journal of Modern Physics B 28, n^o 21 (24 juin 2014) : 1450138. http://dx.doi.org/10.1142/s0217979214501380.

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Geometrical, electronic and magnetic properties of small Au n Ni - (n = 1-9) clusters have been investigated based on density functional theory (DFT) at PW91P86 level. An extensive structural search shows that the relative stable structures of Au n Ni - (n = 1-9) clusters adopt 2D structure for n = 1-5, 7 and 3D structure for n = 6, 8-9. And the substitution of a Ni atom for an Au atom in the [Formula: see text] cluster obviously changes the structure of the host cluster. Moreover, an odd–even alternation phenomenon has been found for HOMO–LUMO energy gaps, indicating that the relative stable structures of the Au n Ni - clusters with odd-numbered gold atoms have a higher relative stability. Finally, the natural population analysis (NPA) and the vertical detachment energies (VDE) are studied, respectively. The theoretical values of VDE are reported for the first time to our best knowledge.

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Shafai, Ghazal S., Sharan Shetty, Sailaja Krishnamurty, Vaishali Shah et D. G. Kanhere. « Density functional investigation of the interaction of acetone with small gold clusters ». Journal of Chemical Physics 126, n^o 1 (7 janvier 2007) : 014704. http://dx.doi.org/10.1063/1.2424458.

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Shi, Yuan-Kun, Zhen Hua Li et Kang-Nian Fan. « Validation of Density Functional Methods for the Calculation of Small Gold Clusters ». Journal of Physical Chemistry A 114, n^o 37 (23 septembre 2010) : 10297–308. http://dx.doi.org/10.1021/jp105428b.

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Sárosi, Menyhárt B., Petronela M. Petrar et R. Bruce King. « Density functional study of bare gold clusters : the ten-vertex neutral system ». Journal of Molecular Modeling 19, n^o 10 (22 août 2013) : 4585–90. http://dx.doi.org/10.1007/s00894-013-1967-9.

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Nicholson, Kenneth T., Kangzhan Zhang, Mark M. Banaszak Holl, F. Read McFeely, Gion Calzaferri et Udo C. Pernisz. « Formation of Mixed Layers Derived from Functional Silicon Oxide Clusters on Gold ». Langmuir 17, n^o 25 (décembre 2001) : 7879–85. http://dx.doi.org/10.1021/la015522m.

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Nguyen Thanh, Si, Huyen Duong Thi, Thao Pham Thi Bich, Kha Tran Ni et Nhat Pham Vu. « A computational study of mercaptopurine and thioguanine binding to gold clusters Aun (n = 3, 4) ». Vietnam Journal of Catalysis and Adsorption 10, n^o 3 (20 août 2021) : xx. http://dx.doi.org/10.51316/jca.2021.058.

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The density functional theory calculations are employed to elucidate the adsorption/desorption behaviours of mercaptopurine (MP) and thioguanine (TG) drugs on the gold surfaces, using Au3 and Au4 clusters as model reactants. The PBE functional in combination with the effective core potential cc-pVTZ-PP basis set for gold atoms and cc-pVTZ basis set for nonmetals have been used to investigated geometric structures, thermodynamic parameters and electronic properties of the obtained complexes. The IEF-PCM model with water solvent was used to include the effect of biological environment on the interactions. The computed results show that the binding is dominated by a covelant bond Au−S and by electrostatic effects, namely a hydrogen bond contribution NH∙∙∙Au. In addition, the drug binding to gold clusters is a reversible process and a drug release mechanism was also clarified. Accordingly, the drugs are willing to separate from the gold surface due to either a slight change of pH in tumor cells or the presence of cysteine residues in protein matrices.

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Ferrari, Piero, Gao-Lei Hou, Olga V. Lushchikova, Florent Calvo, Joost M. Bakker et Ewald Janssens. « The structures of cationic gold clusters probed by far-infrared spectroscopy ». Physical Chemistry Chemical Physics 22, n^o 20 (2020) : 11572–77. http://dx.doi.org/10.1039/d0cp01613f.

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Far-infrared multiple photon dissociation spectroscopy is used in combination with density functional theory calculations to determine the structures of isolated Au_n⁺ (n ≤ 9) clusters.

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Deka, Ajanta. « Preferential Sites for Adsorption of CO on Au6 Clusters Using Density Functional Theory Based Reactivity Descriptors ». Journal of Nanoscience and Nanotechnology 20, n^o 8 (1 août 2020) : 5288–93. http://dx.doi.org/10.1166/jnn.2020.18531.

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Nanoarchitectonics of neutral Au6 cluster upon addition and removal of one electron have been studied using density functional based reactivity descriptors. We studied the response of various sites of cationic, neutral and anionic Au6 clusters towards impending electrophilic and nucleophilic attacks using DFT based local reactivity descriptors, viz, Fukui function for nucleophilic attack f+. Fukui function for electrophilic attack f−, relative nucleophilicity f+/f− and relative electrophilicity f+/f−. Based on these parameters different types of unique atoms have been identified for each cluster. Reactivity predictions for the unique atoms of the minimum energy planar triangular Au6 structure have been verified by using CO as a probe molecule. It has been found adsorption of CO molecules on gold cluster brings about structural changes in the cluster and that the CO molecule prefers the apex site for adsorption onto the triangular Au6 cluster as compared to the mid site.

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Genest, Alexander, Sven Krüger, Alexei B. Gordienko et Notker Rösch. « Gold-Thiolate Clusters : A Relativistic Density Functional Study of the Model Species Au13(SR)n, R = H, CH3, n = 4, 6, 8 ». Zeitschrift für Naturforschung B 59, n^o 11-12 (1 décembre 2004) : 1585–99. http://dx.doi.org/10.1515/znb-2004-11-1232.

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The binding of sulfanyl and alkylsulfanyl model ligands to gold clusters was studied for the case of Au13(SR)n with R = H, CH3 and n = 4, 6, 8. Accurate all-electron electronic structure calculations and geometry optimizations of these gold-thiolate clusters have been performed with a scalar relativistic Kohn-Sham procedure as implemented in the density functional program PARAGAUSS. In all structures obtained, bridge coordination was preferred for both types of ligands; no higher coordinated sites where occupied. While in many cases ligand decoration did not change the overall structure of the Au13 core, also more open structures with Au-Au distances elongated beyond the bulk value have been obtained. The effects due to increasing ligand decoration were small: a small decrease of the binding energy per ligand does not exclude higher ligand coverages. The differences between the model ligands SH and SCH3 were consistent in all cases considered: SCH3 exhibits weaker binding and a slightly smaller charge separation between cluster core and ligand shell, which amounts up to about 1.5 e for 8 ligands. Overall, the Au13 core of the clusters was found to be quite flexible. This can be rationalized by the fact that the calculated binding energy per ligand is comparable or even exceeds the binding energy per atom in Au13.

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Fan, Daoqing, Jiale Ou, Ling Chen, Lichao Zhang, Zhiren Zheng, Haizhu Yu, Xiangming Meng et Manzhou Zhu. « An Oligopeptide-Protected Ultrasmall Gold Nanocluster with Peroxidase-Mimicking and Cellular-Imaging Capacities ». Molecules 28, n^o 1 (21 décembre 2022) : 70. http://dx.doi.org/10.3390/molecules28010070.

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Recent decades have witnessed the rapid progress of nanozymes and their high promising applications in catalysis and bioclinics. However, the comprehensive synthetic procedures and harsh synthetic conditions represent significant challenges for nanozymes. In this study, monodisperse, ultrasmall gold clusters with peroxidase-like activity were prepared via a simple and robust one-pot method. The reaction of clusters with H2O2 and 3,3′,5,5′-tetramethylbenzidine (TMB) followed the Michaelis-Menton kinetics. In addition, in vitro experiments showed that the prepared clusters had good biocompatibility and cell imaging ability, indicating their future potential as multi-functional materials.

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Kizuka, T., et N. Tanaka. « Time-resolved high-resolution electron microscopy of structural stability in mgo clusters ». Proceedings, annual meeting, Electron Microscopy Society of America 54 (11 août 1996) : 672–73. http://dx.doi.org/10.1017/s0424820100165823.

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Structure and stability of atomic clusters have been studied by time-resolved high-resolution electron microscopy (TRHREM). Typical examples are observations of structural fluctuation in gold (Au) clusters supported on silicon oxide films, graphtized carbon films and magnesium oxide (MgO) films. All the observations have been performed on the clusters consisted of single metal element. Structural stability of ceramics clusters, such as metal-oxide, metal-nitride and metal-carbide clusters, has not been observed by TRHREM although the clusters show anomalous structural and functional properties concerning to solid state physics and materials science.In the present study, the behavior of ceramic, magnesium oxide (MgO) clusters is for the first time observed by TRHREM at 1/60 s time resolution and at atomic resolution down to 0.2 nm.MgO and gold were subsequently deposited on sodium chloride (001) substrates. The specimens, single crystalline MgO films on which Au particles were dispersed were separated in distilled water and observed by using a 200-kV high-resolution electron microscope (JEOL, JEM2010) equipped with a high sensitive TV camera and a video tape recorder system.

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Xu, Kang-Ming, Teng Huang, Hui Wen, Yi-Rong Liu, Yan-Bo Gai, Wei-Jun Zhang et Wei Huang. « A density functional study of phosphorus-doped gold clusters : AunP− (n = 1–8) ». RSC Advances 3, n^o 46 (2013) : 24492. http://dx.doi.org/10.1039/c3ra43938k.

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Zhu, Yue, Xin Liu, Min Pu et Fazhi Zhang. « A density functional theory study of gold clusters supported on layered double hydroxides ». Structural Chemistry 25, n^o 3 (13 octobre 2013) : 883–93. http://dx.doi.org/10.1007/s11224-013-0355-5.

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Zhao, Shuang, XinZhe Tian, JunNa Liu, YunLai Ren, YunLi Ren et JianJi Wang. « Density Functional Study of Molecular Hydrogen Adsorption on Small Gold–Copper Binary Clusters ». Journal of Cluster Science 26, n^o 2 (24 janvier 2015) : 491–503. http://dx.doi.org/10.1007/s10876-015-0848-z.

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Ranjan, Prabhat, Tanmoy Chakraborty et Ajay Kumar. « Density functional study of structures, stabilities and electronic properties of AgAunλ(λ=0,±1;n=1-12){\rm{AgAu}}_n^\lambda \left( {\lambda = 0, \pm 1;n = 1 - 12} \right) clusters : comparison with pure gold clusters ». Materials Science-Poland 38, n^o 1 (1 mars 2020) : 97–107. http://dx.doi.org/10.2478/msp-2020-0014.

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AbstractGeometrical structures, relative stabilities and electronic properties of neutral, cationic and anionic pure gold {\rm{A}}u_{n + 1}^\lambda and Ag-doped bimetallic {\rm{AgAu}}_n^\lambda \left( {\lambda = 0, \pm 1;n = 1 - 12} \right) clusters have been systematically investigated by using density functional theory methodology. The optimized structures show that planar to three-dimensional structural transition occurs at n = 5 for cationic clusters. Due to strong relativistic effect of Au clusters, the ground state configurations of neutral and anionic bimetallic clusters favor planar geometry till n = 12. Silver atoms tend to occupy the most highly coordinated position and form the maximum number of bonds with Au atoms. The computed HOMO-LUMO energy gaps, fragmentation energies and second-order difference of energies show interesting odd-even oscillation behavior. The result indicates that AgAu5, {\rm{AgAu}}_2^ + and {\rm{AgAu}}_2^ - are the most stable clusters in this molecular system. The DFT based descriptors of bimetallic clusters are also discussed and compared with pure gold clusters. The high value of correlation coefficient between HOMO-LUMO energy gaps and DFT based descriptors supports our analysis. A good agreement between experimental and theoretical data has been obtained in this study.

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Almeida, Kortney, Katerina Chagoya, Alan Felix, Tao Jiang, Duy Le, Takat B. Rawal, Prescott E. Evans et al. « Methanol carbonylation to acetaldehyde on Au particles supported by single-layer MoS₂ grown on silica ». Journal of Physics : Condensed Matter 34, n^o 10 (24 décembre 2021) : 104005. http://dx.doi.org/10.1088/1361-648x/ac40ad.

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Abstract Homogenous single-layer MoS2 films coated with sub-single layer amounts of gold are found to isolate the reaction of methanol with carbon monoxide, the fundamental step toward higher alcohols, from an array of possible surface reactions. Active surfaces were prepared from homogenous single-layer MoS2 films coated with sub-single layer amounts of gold. These gold atoms formed clusters on the MoS2 surface. A gas mixture of carbon monoxide (CO) and methanol (CH3OH) was partially converted to acetaldehyde (CH3CHO) under mild process conditions (308 kPa and 393 K). This carbonylation of methanol to a C2 species is a critical step toward the formation of higher alcohols. Density functional theory modeling of critical steps of the catalytic process identify a viable reaction pathway. Imaging and spectroscopic methods revealed that the single layer of MoS2 facilitated formation of nanoscale gold islands, which appear to sinter through Ostwald ripening. The formation of acetaldehyde by the catalytic carbonylation of methanol over supported gold clusters is an important step toward realizing controlled production of useful molecules from low carbon-count precursors.

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