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Journal articles on the topic 'Metal Clusters - Structures - Computational Study'

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Published: 7 September 2023

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1

BORRMANN, PETER, BERND DIEKMANN, EBERHARD R. HILF, and DAVID TOMÁNEK. "MAGNETISM OF SMALL TRANSITION-METAL CLUSTERS AND EFFECTS OF ISOMERIZATION." Surface Review and Letters 03, no. 01 (February 1996): 463–66. http://dx.doi.org/10.1142/s0218625x96000838.

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We investigate the magnetic properties of small transition-metal clusters using a simple statistical model, which requires some input data from ab-initio spin-density-functional calculations. In our study, we consider a thermodynamically equilibrated ensemble of clusters with different structures, spin multiplicities, and ground-state energies. We calculate the physical properties of this system by weighting the individual configurations according to the Boltzmann statistics. We find that presence of isomers with very similar ground-state energies, yet very different magnetic properties, gives rise to a rich magnetic behavior of the system which differs significantly from what would be expected for single configurations. We apply the present model to determine the magnetic susceptibility of a cluster ensemble of Langevin paramagnets. Our results show that some of the anomalies in the magnetic behavior of transition-metal clusters might be understood in the framework of our model which is, of course, limited by the extremely high computational effort needed to obtain the input data.
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2

Fotopoulos, Vasileios, David Mora-Fonz, Manuel Kleinbichler, Rishi Bodlos, Ernst Kozeschnik, Lorenz Romaner, and Alexander L. Shluger. "Structure and Migration Mechanisms of Small Vacancy Clusters in Cu: A Combined EAM and DFT Study." Nanomaterials 13, no. 9 (April 25, 2023): 1464. http://dx.doi.org/10.3390/nano13091464.

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Voids in face-centered cubic (fcc) metals are commonly assumed to form via the aggregation of vacancies; however, the mechanisms of vacancy clustering and diffusion are not fully understood. In this study, we use computational modeling to provide a detailed insight into the structures and formation energies of primary vacancy clusters, mechanisms and barriers for their migration in bulk copper, and how these properties are affected at simple grain boundaries. The calculations were carried out using embedded atom method (EAM) potentials and density functional theory (DFT) and employed the site-occupation disorder code (SOD), the activation relaxation technique nouveau (ARTn) and the knowledge led master code (KLMC). We investigate stable structures and migration paths and barriers for clusters of up to six vacancies. The migration of vacancy clusters occurs via hops of individual constituent vacancies with di-vacancies having a significantly smaller migration barrier than mono-vacancies and other clusters. This barrier is further reduced when di-vacancies interact with grain boundaries. This interaction leads to the formation of self-interstitial atoms and introduces significant changes into the boundary structure. Tetra-, penta-, and hexa-vacancy clusters exhibit increasingly complex migration paths and higher barriers than smaller clusters. Finally, a direct comparison with the DFT results shows that EAM can accurately describe the vacancy-induced relaxation effects in the Cu bulk and in grain boundaries. Significant discrepancies between the two methods were found in structures with a higher number of low-coordinated atoms, such as penta-vacancies and di-vacancy absortion by grain boundary. These results will be useful for modeling the mechanisms of diffusion of complex defect structures and provide further insights into the structural evolution of metal films under thermal and mechanical stress.
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3

Marques, J. M. C., F. B. Pereira, J. L. Llanio-Trujillo, P. E. Abreu, M. Albertí, A. Aguilar, F. Pirani, and M. Bartolomei. "A global optimization perspective on molecular clusters." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2092 (March 20, 2017): 20160198. http://dx.doi.org/10.1098/rsta.2016.0198.

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Although there is a long history behind the idea of chemical structure, this is a key concept that continues to challenge chemists. Chemical structure is fundamental to understanding most of the properties of matter and its knowledge for complex systems requires the use of state-of-the-art techniques, either experimental or theoretical. From the theoretical view point, one needs to establish the interaction potential among the atoms or molecules of the system, which contains all the information regarding the energy landscape, and employ optimization algorithms to discover the relevant stationary points. In particular, global optimization methods are of major importance to search for the low-energy structures of molecular aggregates. We review the application of global optimization techniques to several molecular clusters; some new results are also reported. Emphasis is given to evolutionary algorithms and their application in the study of the microsolvation of alkali-metal and Ca 2+ ions with various types of solvents. This article is part of the themed issue ‘Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces’.
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Ngan, Vu Thi, Philipp Gruene, Pieterjan Claes, Ewald Janssens, André Fielicke, Minh Tho Nguyen, and Peter Lievens. "Disparate Effects of Cu and V on Structures of Exohedral Transition Metal-Doped Silicon Clusters: A Combined Far-Infrared Spectroscopic and Computational Study." Journal of the American Chemical Society 132, no. 44 (November 10, 2010): 15589–602. http://dx.doi.org/10.1021/ja105099u.

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5

Catlow, C. R. A., S. A. French, A. A. Sokol, and J. M. Thomas. "Computational approaches to the determination of active site structures and reaction mechanisms in heterogeneous catalysts." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 363, no. 1829 (April 15, 2005): 913–36. http://dx.doi.org/10.1098/rsta.2004.1529.

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We apply quantum chemical methods to the study of active site structures and reaction mechanisms in mesoporous silica and metal oxide catalysts. Our approach is based on the use of both molecular cluster and embedded cluster (QM/MM) techniques, where the active site and molecular complex are described using density functional theory (DFT) and the embedding matrix simulated by shell model potentials. We consider three case studies: alkene epoxidation over the microporous TS-1 catalyst; methanol synthesis on ZnO and Cu/ZnO and C–H bond activation over Li-doped MgO.
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6

LOPES, JULIANA FEDOCE, JÚLIO C. S. DA SILVA, WILLIAN R. ROCHA, WAGNER B. DE ALMEIDA, and HÉLIO F. DOS SANTOS. "QUANTUM CHEMICAL STUDY OF CISPLATIN-WATER COMPLEXES: AN INVESTIGATION OF ELECTRON CORRELATION EFFECTS." Journal of Theoretical and Computational Chemistry 10, no. 03 (June 2011): 371–91. http://dx.doi.org/10.1142/s0219633611006517.

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The interaction of cisplatin ([ Pt(NH3)2Cl2] ) with water was studied for distinct complexation modes aiming to investigate the level of calculation required to describe transition metal complexes of biological relevance, where large scale ab initio post-Hartree-Fock calculations are usually precluded. Coupled Cluster (CCSD(T)) single point calculations employing MP2 and MP4(SDQ) optimized geometries and good quality basis sets, using effective core potential for platinum atom, are reported as well as Density Functional Theory (DFT) results employing various exchange-correlation functional. The importance of electron correlation effects for the calculation of interaction energies is discussed. The extension of correlation energy recovered by DFT was assessed considering the CCSD(T) results as reference. The recently developed M06-2x functional showed the best overall agreement with CCSD(T) calculations. The relative importance of the electrostatic and dispersion contributions to the interaction energy was estimated with the aid of the atoms in molecules theory and also using an empirical approach based on the multipole expansion method. It was found a strong dependence of the energy contributions on the spatial orientation of water and cisplatin monomers, with the electrostatic contribution dominating the interaction energy for the lowest energy equilibrium structures.
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7

Zhao, Run-Ning, Yanhong Yuan, and Ju-Guang Han. "Transition metal Mo-doped boron clusters: A computational investigation." Journal of Theoretical and Computational Chemistry 13, no. 05 (August 2014): 1450036. http://dx.doi.org/10.1142/s0219633614500369.

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Geometries associated with relative stabilities and energy gaps of the Mo -doped boron clusters have been investigated systematically by using density functional theory. The critical size of Mo -encapsulated B n structures emerges as n = 10, the evaluated relative stabilities in term of the calculated fragmentation energies reveal that the MoB 6 has enhanced stabilities over their neighboring clusters. Furthermore, the calculated polarities of the MoB n reveal that the hypercoordinated planar MoB 10 wheel is a weakened polar molecule and MoB 11 ring is a nonpolar molecule, and aromatic properties are discussed. Additionally, the MoB 10 cluster with smaller highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap is supposed to be stronger chemical activity and smaller chemical hardness. Moreover, the recorded natural populations show that the charges transfer from boron framework to Mo atom. It should be pointed out that the remarkable charge-transfer features of MoB n clusters are distinctly similar to those of transitional metal (TM)-doped Si n clusters; growth-pattern of the TMBn depends on the doped TM impurity.
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8

Addicoat, Matthew A., and Gregory F. Metha. "Computational Study of CO Reactivity with Nb3X Heteronuclear Clusters." Australian Journal of Chemistry 61, no. 11 (2008): 854. http://dx.doi.org/10.1071/ch08269.

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Density functional calculations were performed to determine the equilibrium structures, ionization potentials, and electron affinities of Nb3X clusters (X = Na, Al, Sc, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd). Pseudo-tetrahedral geometries were preferred for all Nb3X clusters except Nb3Cd. The equilibrium structures and binding energies of the associatively and dissociatively bound products of the Nb3X + CO reaction were calculated at the same level of theory. All clusters were found to thermodynamically dissociate CO. Only Nb3Al and Nb3Cd reduced the enthalpy of dissociation relative to Nb4, whereas all other heteroatoms increased it.
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9

Chen, Sian, Haining Wang, Shanfu Lu, and Yan Xiang. "Monolayer MoS2 film supported metal electrocatalysts: a DFT study." RSC Advances 6, no. 109 (2016): 107836–39. http://dx.doi.org/10.1039/c6ra23995a.

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10

Álvarez-Zapatero, Pablo, and Andrés Aguado. "Computational characterisation of structure and metallicity in small neutral and singly-charged cadmium clusters." Physical Chemistry Chemical Physics 21, no. 23 (2019): 12321–34. http://dx.doi.org/10.1039/c9cp01814j.

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Putative global minimum structures and an analysis of the electronic structure of neutral and charged cadmium clusters are reported to gain insight into the gradual insulator-to-metal transition in the small-size regime.
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11

Grimes, Robin W., and David Onwood. "Computational study of the formation of metal-oxide diatomics and clusters." Journal of the Chemical Society, Faraday Transactions 86, no. 2 (1990): 233. http://dx.doi.org/10.1039/ft9908600233.

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12

Wu, Ping, Min Huang, Naiqiang Yin, and Peng Li. "The Modulation Effect of MoS2 Monolayers on the Nucleation and Growth of Pd Clusters: First-Principles Study." Nanomaterials 9, no. 3 (March 8, 2019): 395. http://dx.doi.org/10.3390/nano9030395.

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The geometries, electronic structures, adsorption, diffusion, and nucleation behaviors of Pdn (n = 1–5) clusters on MoS2 monolayers (MLs) were investigated using first principles calculations to elucidate the initial growth of metal on MoS2. The results demonstrate that Pd clusters can chemically adsorb on MoS2 MLs forming strong Pd–S covalent bonds with significant ionic character. We investigated the initial growth mode of Pd clusters on MoS2 monolayers and found that Pdn clusters tend to adopt pyramid-like structures for n = 4–5 and planar structures lying on MoS2 substrates for n = 1–3. It can be explained by the competition between adsorbate–substrate and the intra-clusters’ interactions with the increasing coverage. Compared with pristine MoS2 MLs, the work function was reduced from 5.01 eV upon adsorption of Pd monomer to 4.38 eV for the case of the Pd5 clusters due to the charge transfer from Pd clusters to MoS2 MLs. In addition, our calculations of the nucleation and diffusion behaviors of Pd clusters on MoS2 MLs predicted that Pd is likely to agglomerate to metal nanotemplates on MoS2 MLs during the epitaxial stacking process. These findings may provide useful guidance to extend the potential technological applications of MoS2, including catalysts and production of metal thin films, and the fabrication of nanoelectronic devices.
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13

Mohajeri, Afshan, and Mahsa Ebadi. "Nano Structures of Group 13–15 Mixed Heptamer Clusters: A Computational Study." Journal of Physical Chemistry A 116, no. 18 (April 27, 2012): 4678–86. http://dx.doi.org/10.1021/jp302323x.

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14

Jeon, In-Sun, Doo-Sik Ahn, Sung-Woo Park, Sungyul Lee, and Bongsoo Kim. "Structures and isomerization of neutral and zwitterion serine-water clusters: Computational study." International Journal of Quantum Chemistry 101, no. 1 (October 19, 2004): 55–66. http://dx.doi.org/10.1002/qua.20269.

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15

Wang, Youliang, and John R. Gunn. "Computational study on small water clusters using a semiempirical valence bond approach." Canadian Journal of Chemistry 77, no. 3 (March 1, 1999): 367–77. http://dx.doi.org/10.1139/v99-021.

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Small clusters of water (H2O)n, n = 3-8, are studied using a semiempirical valence bond approach to investigate the bonding energy contribution and hydrogen-bonding structure in the most stable conformation. The energy contribution was decomposed into electron pair-pair interactions and valence-bond energy for each water monomer. Our study shows that there is significant bonding difference between small clusters (n [Formula: see text] 5) of water and larger clusters (n > 5). In the larger clusters, there are structures containing tetravalent oxygen centers, which is impossible in the small clusters. The contribution to the binding energy from each H-bond varies from -4.7 kcal/mol to -7.3 kcal/mol in the water clusters considered here. The contribution of -5.9 kcal/mol per H-bond in the cubic octamer is comparable to the experimental value (-6.7 kcal/mol) of the binding energy in ice.Keywords: semi-empirical, valence bond, hydrogen bonding, water clusters.
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16

Bui, Thanh Tho, Khung Moc Trang, and Hong Van Nguyen. "Theoretical study on structures and magnetic properties of NaxV (x=1-12) atomic clusters." Science and Technology Development Journal 18, no. 2 (June 30, 2015): 177–86. http://dx.doi.org/10.32508/stdj.v18i2.1183.

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Superatoms, novel entities have been studied extensively in recent years, can be stabilized by mixing with transition metal atoms for forming atomic clusters. The aim of this contribution is to present some recent theoretical results on the application of quantum calculations for examining the structures and magnetic properties of the atomic clusters NaxV (x=1-12) made from the mixing of Nax superatoms with vanadium, a transition metal atom. Optimized structures of NaxV (x=1-12) are determined by using the TPSSTPSS/DGDZVP DFT calculations. Characteristics of optimized structures, as structural parameters, values of the magnetic moment on the atomic orbitals are determined. The obtained results point out that: (1) the Na8V cluster is the most stable in NaxV (x=1-12) atomic clusters and (2) the value of themagnetic moment of Na8V cluster is mainly influenced by the orbital magnetic momentof the atom V and this is an interesting difference from other remaining NaxV(x≠8) clusters
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17

Han, Ju-Guang, and Frank Hagelberg. "Recent progress in the computational study of transition metal doped Si clusters." Computing Letters 1, no. 4 (March 6, 2005): 230–39. http://dx.doi.org/10.1163/157404005776611493.

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Computational investigations on silicon clusters (Sin) in combination with atomic transition metal (TM) impurities are reviewed in this contribution. Emphasis is placed on studies that focus on the size exohedral to endohedral evolution features of TMSin, such as the critical ligand number for the transition from equilibrium geometry. Geometric, energetic, electronic and magnetic characteristic of TMSin are discussed in the size region n ≤ 20. It is pointed out that selected TMSin systems with n = 12 and n = 16 emerge from present computational research as the most promising candidates for building blocks of novel nanomaterials.
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18

Derepas, A. L., J. M. Soudan, V. Brenner, J. P. Dognon, and Ph Millié. "Can we understand the different coordinations and structures of closed-shell metal cation-water clusters?" Journal of Computational Chemistry 23, no. 10 (May 21, 2002): 1013–30. http://dx.doi.org/10.1002/jcc.10063.

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19

Sharma, Divya, and Martin J. Paterson. "Ground and excited states of naphthalene–water (naphtha–W6) clusters: a computational study." RSC Advances 5, no. 36 (2015): 28281–91. http://dx.doi.org/10.1039/c5ra01894c.

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20

XUE, Z. Q., H. J. GAO, W. M. LIU, Y. W. LIU, Q. D. WU, and S. J. PANG. "STUDY OF METALLIC CLUSTERS IN ORGANIC THIN FILMS." Surface Review and Letters 03, no. 01 (February 1996): 1029–32. http://dx.doi.org/10.1142/s0218625x96001844.

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The polyethylene (PE) and the metallic materials are deposited alternatively on substrates in the chamber of the ICB-TOFMS deposition system. The metallic-cluster-polyethylene thin films are formed. The film thickness is about 30 nm. The structures of these samples including Au-PE, Ag-PE, In-PE, and Sn-PE thin films are studied. These special thin films with suspension metal clusters display many special properties.
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21

ZHAO, JIJUN, XIAOSHUANG CHEN, FENGQI LIU, and GUANGHOU WANG. "ELECTRON–PHONON INTERACTION AND ELECTRONIC STRUCTURE OF SMALL METAL CLUSTERS." Surface Review and Letters 03, no. 01 (February 1996): 489–92. http://dx.doi.org/10.1142/s0218625x96000887.

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The Su–Schrieffer–Heeger (SSH) Hamiltonian has been extended to study the electron–phonon interaction and the electronic structures of the alkali-like metal clusters. The eigen-energy levels of s valence electrons are obtained from a Hückel-like Hamiltonian including the correction of the electron–phonon interaction in the hopping integral, which is proportional to the variable of bond length. The self-consistent equations for electrons and phonons are solved adiabatically through an iteration process. The energy-level structures of an octahedral Cu6 cluster are calculated with variable electron–phonon coupling constant λ to investigate the influence of electron–phonon interaction on the lattice distortion and electronic structures of metal clusters. The size-dependent ionization potential for small Cun clusters are calculated and compared with the experimental results.
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22

Wu Li-Jun, Sui Qiang-Tao, Zhang Duo, Zhang Lin, and Qi Yang. "Computational study of structures and electronic properties of SimGen (m+n=9) clusters." Acta Physica Sinica 64, no. 4 (2015): 042102. http://dx.doi.org/10.7498/aps.64.042102.

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23

Bui, Thanh Tho, Khung Moc Trang, and Hong Van Nguyen. "Study on structures and electronic properties of NaxV (x=1-12) atomic clusters." Science and Technology Development Journal 17, no. 4 (December 31, 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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24

PANDEY, ANOOP, APOORVA DWIVEDI, SAIKAT MUKHOPADHYAY, and NEERAJ MISRA. "AB INITIO STUDY OF DIFFERENT PROBABLE STRUCTURES OF GROUP III ANTIMONIDES." Journal of Theoretical and Computational Chemistry 12, no. 06 (September 2013): 1350056. http://dx.doi.org/10.1142/s0219633613500569.

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Ab initio studies of the small ( AlSb , InSb , GaSb ) clusters is performed to investigate the changes in structural, vibrational and electronic properties. The calculated results clearly demonstrate that any change in the electronic configuration of the neutral clusters gives rise to noticeable changes in the structure. The structures of the neutral, positively and negatively charged clusters are fully optimized, taking the importance of the symmetry into account in all the cases. The changes in vibrational properties are explained keeping in mind the change in the interatomic distances due to any change in the electronic configuration.
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25

Wang, Jing, Yang Zhao, Jun Li, Hai-Cai Huang, Jing Chen, and Shi-Bo Cheng. "Unveiling the electronic structures and ligation effect of the superatom–polymeric zirconium oxide clusters: a computational study." Physical Chemistry Chemical Physics 21, no. 27 (2019): 14865–72. http://dx.doi.org/10.1039/c9cp01870k.

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26

Nguyen, Hong Van, That Van Nguyen, Bong Thi Le, Huong Thi Thanh Do, and 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, no. 2 (May 16, 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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27

Huu, Tho, and Tam Nguyen Minh. "A theoretical study of the first-row transition metal doped germanium clusters Ge14M." Journal of Military Science and Technology 87 (May 25, 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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Prakash, Rini, Jean-François Halet, and Sundargopal Ghosh. "Polyhedral [M2B5] Metallaborane Clusters and Derivatives: An Overview of Their Structural Features and Chemical Bonding." Molecules 25, no. 14 (July 12, 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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Qin, Zhengbo, Jiangle Zhang, Chen Wang, Lin Wang, and Zichao Tang. "Does gold behaves as hydrogen? A joint theoretical and experimental study." Nanoscale Advances 2, no. 2 (2020): 844–50. http://dx.doi.org/10.1039/c9na00780f.

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It has been established that noble-metal–H analogue has been found in plenty of noble-metal–ligand clusters in view of geometric and electronic structures. Now, it is beyond the analogy in the complexes of M(SCH3)2− (M = Cu, Ag, Au and H).
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Min, Ahreum, Ahreum Ahn, Cheol Joo Moon, Ji Hoon Lee, Yeon Guk Seong, Seong Keun Kim, and Myong Yong Choi. "Conformational structures of jet-cooled acetaminophen–water clusters: a gas phase spectroscopic and computational study." Physical Chemistry Chemical Physics 19, no. 6 (2017): 4840–48. http://dx.doi.org/10.1039/c6cp06863d.

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Jet-cooled acetaminophen (AAP)–water clusters, AAP–(H2O)1, have been investigated by a combination of theoretical calculations and R2PI, UV–UV HB, IR-dip, IR–UV HB techniques in the gas phase.
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31

Li, Xiaojun, and Denghui Xing. "Systematic Theoretical Study of Electronic Structures and Stability of Transition-Metal-Adsorbed Graphdiyne Clusters." Journal of Physical Chemistry C 123, no. 14 (March 15, 2019): 8843–50. http://dx.doi.org/10.1021/acs.jpcc.8b11572.

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32

Ren, Fang-Qin, Fu-Qiang Zhang, Ya-Fen Li, Jin Lv, and Wen-Jin Ma. "Density functional study of the structural, stability, magnetic properties and chirality of small-sized AlxZry (x+y≤9) alloy clusters." Journal of Theoretical and Computational Chemistry 16, no. 07 (November 2017): 1750058. http://dx.doi.org/10.1142/s0219633617500584.

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The equilibrium structures, stabilities, magnetic, and spectroscopic properties of small-sized AlxZry ([Formula: see text]) alloy clusters have been systematically investigated within the framework of density functional theory. We found that the structures of bimetallic clusters prefer to form the same motif as their corresponding pure Al or Zr clusters and chirality turns up in mixed clusters with [Formula: see text] and 9. Computations of VCD and VROA spectra confirmed the chirality of these clusters. For a given cluster size, the most favorable mixing occurs when the ratio of Al:Zr is approximatively equal to 1. The total magnetic moments depend not only on the configuration but also on the composition of the clusters.
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33

Martinez, Arturo I. "Computational Study of Organometallic Structures for Hydrogen Storage, Effects of Ligands." Journal of Nano Research 5 (February 2009): 113–19. http://dx.doi.org/10.4028/www.scientific.net/jnanor.5.113.

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Density functional theory calculations of hydrogen storage capacity for different organometallic structures have been carried out. Complexes involving Sc, Ti and V bound to C4H4, C5H5, C5F5 and B3N3H6 molecules have been considered, and all present a hydrogen storage capability limited by the 18-electron rule. In order to stabilize the complexes, which the 18-electron rule is not completed, additional ligands are considered, namely -H, -CH3, -NH2, -OH and -F. These ligands affect the H2-metal bond; particularly the back donation effect from the metal atom to the * antibonding state of H2 and then its H2 storage capacity.
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34

Batra, Prinka, Ritu Gaba, Upasana Issar, and Rita Kakkar. "Structures and Stabilities of Alkaline Earth Metal Oxide Nanoclusters: A DFT Study." Journal of Theoretical Chemistry 2013 (October 24, 2013): 1–14. http://dx.doi.org/10.1155/2013/720794.

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The stability orders of a number of alkaline earth oxide cluster isomers (MO)n, M = Mg, Ca, Sr, Ba and 1≤n≥6 have been determined by means of density functional theory studies using the LDA-PWC functional. Among the candidate structures, the hexagonal-ring-based isomers and the slab shapes are found to display similar stabilities. Stacks of hexagonal (MO)3 rings are found to be the slightly preferred growth strategy among the (MgO)6, isomers. In contrast, the slab structures are slightly preferred for the other alkaline metal oxide (MO)6 clusters. An explanation based on packing and aromaticity arguments has been proposed. This study may have important implications for modeling and understanding the initial growth patterns of small nanostructures of alkaline earth metals.
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35

Tran, Dung T., and Roy L. Johnston. "Study of 40-atom Pt–Au clusters using a combined empirical potential-density functional approach." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 467, no. 2131 (March 9, 2011): 2004–19. http://dx.doi.org/10.1098/rspa.2010.0562.

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This work is a theoretical study of 40-atom Pt–Au clusters which are of interest owing to the electronic shell closure of 40-atom noble metal clusters and the current focus on bimetallic Pt–Au clusters as catalysts. The methodology is a complementary combination of a genetic algorithm search for an empirical potential and density functional theory (DFT) reoptimization. Structures based on truncated-octahedral, icosahedral, decahedral and fivefold pancake geometries are found to be energetically favoured for different composition regions at the empirical-potential level and this is partially confirmed at the DFT level. The large HOMO–LUMO gaps found for the icosahedral and fivefold pancake structures indicate electronic shell closure effects, while the truncated-octahedral and decahedral structures have small gaps. The DFT calculations confirm that, for Pt 20 Au 20 truncated-octahedral structures, the Pt core Au shell configuration which has two Au atoms capping the (100) facets is most energetically favoured, and the layered (phase segregated) configuration also has lower energy compared with the Au core Pt shell and mixed configurations.
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36

Gutsev, G. L., K. G. Belay, K. V. Bozhenko, L. G. Gutsev, and B. R. Ramachandran. "A comparative study of small 3d-metal oxide (FeO)n, (CoO)n, and (NiO)n clusters." Physical Chemistry Chemical Physics 18, no. 40 (2016): 27858–67. http://dx.doi.org/10.1039/c6cp03241a.

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Geometrical and electronic structures of the 3d-metal oxide clusters (FeO)n, (CoO)n, and (NiO)n are computed using density functional theory with the generalized gradient approximation in the range of 1 ≤ n ≤ 10.
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37

Kua, Jeremy, and Keaton M. Tomlin. "Computational Study of Multiple-Decker Sandwich and Rice-Ball Structures of Neutral Titanium−Benzene Clusters." Journal of Physical Chemistry A 110, no. 43 (November 2006): 11988–94. http://dx.doi.org/10.1021/jp065341z.

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38

Li, Qing-Shan, Bingyi Song, Limei Wen, Li-Ming Yang, and Eric Ganz. "Elucidation of Structures, Electronic Properties, and Chemical Bonding of Monophosphorus-Substituted Boron Clusters in Neutral, Negative, and Positively Charged PBn/PBn–/PBn+ (n = 4–8)." Condensed Matter 7, no. 4 (November 12, 2022): 66. http://dx.doi.org/10.3390/condmat7040066.

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This paper reports the computational study of phosphorus-doped boron clusters PBn/PBn–/PBn+ (n = 4–8). First, a global search and optimization of these clusters were performed to determine the stable structures. We used density functional theory (DFT) methods and ab initio calculations to study the stability of the atomic clusters and to explore the arrangement of stable structures. We found that the lowest energy structures of the smaller phosphorus-doped boron clusters tend to form planar or quasi-planar structures. As additional boron atoms are added to the smallest structures, the boron atoms expand in a zigzag arrangement or in a net-like manner, and the phosphorus atom is arranged on the periphery. For larger structures with seven or eight boron atoms, an unusual umbrella-like structure appears. We calculated the binding energy as well as other energies to study cluster stability. We calculated the ionization energy, electron affinity, and the HOMO–LUMO gaps. In addition, we used the adaptive natural density partitioning program to perform bond analysis so that we have a comprehensive understanding of the bonding. In order to have a suitable connection with the experiment, we simulated the infrared and photoelectron spectra.
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39

Kavitha, Subramaniam, Palanisamy Deepa, Mylsamy Karthika, and Ramasamy Kanakaraju. "Topological analysis of metal–ligand and hydrogen bonds in transition metal hybrid structures – A computational study." Polyhedron 115 (September 2016): 193–203. http://dx.doi.org/10.1016/j.poly.2016.05.010.

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40

Prudente, Frederico V., and Jorge M. C. Marques. "Thermodynamic Signatures of Structural Transitions and Dissociation of Charged Colloidal Clusters: A Parallel Tempering Monte Carlo Study." Molecules 27, no. 8 (April 16, 2022): 2581. http://dx.doi.org/10.3390/molecules27082581.

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Computational simulation of colloidal systems make use of empirical interaction potentials that are founded in well-established theory. In this work, we have performed parallel tempering Monte Carlo (PTMC) simulations to calculate heat capacity and to assess structural transitions, which may occur in charged colloidal clusters whose effective interactions are described by a sum of pair potentials with attractive short-range and repulsive long-range components. Previous studies on these systems have shown that the global minimum structure varies from spherical-type shapes for small-size clusters to Bernal spiral and “beaded-necklace” shapes at intermediate and larger sizes, respectively. In order to study both structural transitions and dissociation, we have organized the structures appearing in the PTMC calculations by three sets according to their energy: (i) low-energy structures, including the global minimum; (ii) intermediate-energy “beaded-necklace” motifs; (iii) high-energy linear and branched structures that characterize the dissociative clusters. We observe that, depending on the cluster, either peaks or shoulders on the heat–capacity curve constitute thermodynamics signatures of dissociation and structural transitions. The dissociation occurs at T=0.20 for all studied clusters and it is characterized by the appearance of a significant number of linear structures, while the structural transitions corresponding to unrolling the Bernal spiral are quite dependent on the size of the colloidal system.
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41

Han, Ju-Guang, and Frank Hagelberg. "Recent Progress in the Computational Study of Silicon and Germanium Clusters with Transition Metal Impurities." Journal of Computational and Theoretical Nanoscience 6, no. 2 (February 1, 2009): 257–69. http://dx.doi.org/10.1166/jctn.2009.1035.

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42

Szaro, Nicholas, and Andreas Heyden. "A DFT+U Study of the Electrochemical Oxidation of H2 and CO on SrLaFeO4-Δ." ECS Meeting Abstracts MA2022-01, no. 46 (July 7, 2022): 1970. http://dx.doi.org/10.1149/ma2022-01461970mtgabs.

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INTRODUCTION Solid oxide fuel cell (SOFC) anodes are commonly composed of cermet materials, typically Ni-YSZ. Despite success in electrochemical performance, cermet materials suffer from sulfur poisoning, coke formation under low operating temperatures, and metal coarsening. Due to success of material design focused on the cathode such as LSCF, single-phase mixed ionic-electronic conducting (MIEC) materials have displayed promising oxidation activity [1]. The Sr-based Ruddlesden-Popper (RP) family has found recent use as a base stoichiometry in anodes where experimentalists have used both A and B-site doping and nanoparticle exsolvation strategies in order to tune activity [2,3]. In order to understand the fundamental electrochemical activity, we want to elaborate on the mechanism of H2 and CO oxidation on the promising material SrLaFeO4- 𝛿 (SLF). In the present study, we used ab initio methods to model H2 and CO oxidation on two FeO2-based models of SLF with and without B-site doping with Co and Ni. COMPUTATIONAL DETAILS All calculations presented in this work were performed using the spin-polarized DFT+U method with periodic boundary conditions as implemented in the VASP 5.4.4 code. We choose the PBE functional to describe exchange and correlation effects. Dudarev’s approach for DFT+U calculations is used with a U-J value of 4.0, 3.32, and 6.2 eV, respectively. We used the projector-augmented wave (PAW) method to represent the inner core potentials. The kinetic energy cutoff was set for all calculations to 700 eV, and integration over the Brillouin zone was performed with 3 × 3 × 1 Monkhorst-Point k-point mesh and the Gaussian smearing method with a sigma value of 0.05 eV. Slab models utilized a 15 Å vacuum layer and the bottom two layers were fixed to bulk position values. The DFT-derived parameters were employed in a microkinetic model to calculate the surface coverage of all adsorbed species for a given reaction condition. RESULTS AND DISCUSSION To begin our study, we tested all non-symmetrical conformers of SLF for the lowest relative energy on a model 2 × 2 × 1 supercell, as displayed in Figure 1a. A total of 3 structures were tested – P4/mmm, P4/nmm, and I4mm. We confirm that the lowest energy structure (I4mm) is equivalent to the experimentally reported structure. Next, we develop two 1.5 × 1.5 × 1 non-identical (001) FeO2-based slab models – so-called FeO2-LaO and FeO2-SrO (Figure 2b). The oxidation mechanism of H2 suggests oxidation begins with a dissociative adsorption step. Subsequent steps include formation of surface H2O, a surface vacancy, and a subsurface vacancy. To complete the catalytic cycle, we computed the bulk vacancy migration of SLF and assumed fast cathode kinetics for the overall cell model. At an operating voltage of 0.7 V, we predict that the highest rate occurs on the FeO2-SrO surface. We predict that H2 dissociative adsorption step is the rate-determining process based on Campbell’s degree of rate control. With the application of a single B-site dopant (Co and Ni), Co and Ni both decrease the barrier of the H2 dissociative adsorption step. Ni causes a slight decrease in energy for the formation energy of H2O. The oxidation mechanism of CO suggests oxidation begins with adsorption of the CO molecule on a reduced Fe site. The CO migrates to a neighboring Fe-O complex in order to form surface CO2. Based on degree of rate control, CO2 formation is likely the rate-determining step for both surface models. In conclusion, this is one of the first mechanism investigations on the anodic oxidation reactions of H2 and CO on RP-based oxides. We find that H2 has promising catalytic performance similar to the experimental evidence. The inclusion of B-site dopants displays that catalytic performance can be tuned with the introduction of different transition metals. Future work will examine the role of exsolved particles for RP-based oxides. ACKNOWLEDGMENTS This work has been funded by the Division of Materials Research, a National Science Foundation organization under Award Number 1832809. Computing resources provided by the San Diego Supercomputer Center (SDSC) and Texas Advanced Computing Center (TACC) under XSEDE grant number TG-CTS090100 and USC High-Performance Computing clusters are gratefully acknowledged. REFERENCES L. Xu, Y. Yin, N. Wang, Z. Ma, Electrochem. Commun., 76, 51–54 (2017) N. Wu, W. Wang, Y. Zhong, G. Yang, J. Qu, Z. Shao, ChemElectroChem, 4, 2378–2384 (2017) H. Chong, H. Chen, Z. Shao, J. Shi, J. Bai, S. Li, J. Mater. Chem. A, 4, 13997–14007 (2016) FIGURE 1a: 2×2×1 supercell model of I4mm SrLaFeO4 FIGURE 1b: Slab models of (001) FeO2-LaO and FeO2-SrO Figure 1
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43

BÖYÜKATA, MUSTAFA. "MOLECULAR DYNAMICS STUDY OF Tin, Vn AND Crn CLUSTERS." Journal of Theoretical and Computational Chemistry 06, no. 01 (March 2007): 81–97. http://dx.doi.org/10.1142/s0219633607002873.

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Using a Morse type pair potential, molecular-dynamics simulations have been performed to investigate the atomic geometries, growing patterns, structural stabilities, energetics and magic sizes of Ti n, V n and Cr n (n = 2-50) clusters. Following rearrangement collision of the atom–cluster system in fusion process, and absorbing their energies step by step down to 0 K, possible optimal equilibrium geometries of the clusters have been generated to tackle the structural determination problem. This approach serves an efficient alternative to the growing path identification and the optimization techniques. It has been found that titanium, vanadium and chromium clusters prefer to form three-dimensional compact structures in the determined configurations and the appearances of medium sizes are, in general, five-fold symmetry on the spherical clusters. Moreover, relevant relations between atomic arrangements in the clusters and the magic sizes have been observed.
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44

Nguyen Minh, Thao, and Thanh Bui Tho. "Study the structure, stability and CO2 adsorption of the ScVB5 cluster." Vietnam Journal of Catalysis and Adsorption 11, no. 1 (August 20, 2021): 48–58. http://dx.doi.org/10.51316/jca.2022.008.

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A combination of genetic algorithm and density functional theory (GA-DFT) was used to calculate the minimum structures of ScVB5 clusters. The thirteen isomers of ScVB5 cluster were investigated at the level of PBE/def2-TZVPP, TPSSh/def2-TZVPP, and TPSSh/def2-QZVP levels. The relative energies, the structural geometry, ionization energy, affinity energy of neutral isomers were reported. The ScVB5 cluster can be formed by adding atom into smaller clusters. The proposed structure of ScVB5 cluster for CO2 treatment is a pentagonal bipyramid in the Cs symmetry with vanadium atom at one of the vertices and scandium atom in the base of bipyramid. The favor position for adsorp CO2 by the ScVB5 cluster were at around of Sc and V atoms. The dual transition metal-doped boron clusters can interact with CO2 molecules stronger than pure boron clusters.
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45

Tsona, Narcisse T., Henning Henschel, Nicolai Bork, Ville Loukonen, and Hanna Vehkamäki. "Structures, Hydration, and Electrical Mobilities of Bisulfate Ion–Sulfuric Acid–Ammonia/Dimethylamine Clusters: A Computational Study." Journal of Physical Chemistry A 119, no. 37 (September 2015): 9670–79. http://dx.doi.org/10.1021/acs.jpca.5b03030.

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46

Dai, Ying, Bai Biao Huang, Run Long, and Lin Yu. "Theoretical Study of Differences between Surface and Bulk Electronic States in Cu Clusters." Solid State Phenomena 121-123 (March 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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47

JIA, JIN-FENG, X. LIU, S. C. LI, J. Z. WANG, J. L. LI, H. LIU, M. H. PAN, et al. "ARTIFICIAL METAL NANOCLUSTER CRYSTALS." Modern Physics Letters B 16, no. 23n24 (October 20, 2002): 889–94. http://dx.doi.org/10.1142/s0217984902004408.

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Artificial metal nanocluster crystals, (i.e. periodic lattices consisting of identical metal nanoclusters) were fabricated using a novel technique in which surface mediated magic clustering was used to achieve identical cluster size, while the Si(111)-7 × 7 surface was used as a template for ordering the clusters. The universality of this strategy was demonstrated by fabricating more than 10 different nanocluster arrays with different metals and alloys. The atomic structures, formation mechanism and stability of the nanoclusters were studied with in situ scanning tunneling microscopy combined with first-principles total energy calculations. Our study shows that delicate control of growth kinetics is extremely important for cluster crystal fabrication.
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48

Nguyen, Huu Tho, Ngo Tuan Cuong, Ngo Thi Lan, Nguyen Thanh Tung, Minh Tho Nguyen, and Nguyen Minh Tam. "First-row transition metal doped germanium clusters Ge16M: some remarkable superhalogens." RSC Advances 12, no. 21 (2022): 13487–99. http://dx.doi.org/10.1039/d1ra08527a.

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A theoretical study of geometric and electronic structures, stability and magnetic properties of both neutral and anionic Ge16M0/− clusters with M being a first-row 3d transition metal atom, is performed using quantum chemical approaches.
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49

Okumoto, Satoshi, and Shinichi Yamabe. "Water-trimer clusters as nucleophilic reagents in hydrolyses of substrates for metal–alkoxides – a computational study." Journal of Non-Crystalline Solids 291, no. 3 (October 2001): 167–75. http://dx.doi.org/10.1016/s0022-3093(01)00808-0.

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50

Zabardasti, Abedien, Nahid Zare, Masoumeh Arabpour, Ali Kakanejadifard, and Mohammad Solimannejad. "Theoretical Study of Mixed Hydrogen and Dihydrogen Bond Interactions in Clusters." Journal of Chemistry 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/194836.

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Ab initio calculations were used to analyze interactions of with 1–4 molecules of NH3at the MP2/6-311++G(d,p) and the B3LYP/6-311++G(d,p) computational levels. In addition to H3B–H⋯H–NH2dihydrogen bond, the H2N–H⋯NH3hydrogen bonds were also predicted in clusters. Negative cooperativity in clusters constructed from mixed H3B–H⋯H–NH2dihydrogen and H2N–H⋯NH3hydrogen bonds are more remarkable. The negative cooperativity increases with size and number of hydrogen bonds in cluster. The B–H stretching frequencies show blue shifts with respect to cluster formation. Greater blue shift in stretching frequencies was predicted for B–H bonds which did not contribute to dihydrogen bonding with NH3molecules. The structures were analyzed with the atoms in molecules (AIM) methodology.
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