Progress in Experimental and Theoretical Studies of Clusters

Kondow, Tamotsu; Mafuné, F.

doi:10.1142/4119

Cited by 20 publications

(13 citation statements)

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“…Angle-resolved photoemission is also used for free clusters, which are interesting systems both for a fundamental understanding of the many-body problem and for practical nanotechnological applications. 12,13 The study of the angular distribution of photoelectrons can unravel cluster size effects that underline the transition from individual atoms and molecules to larger systems, finally evolving to the solid state behavior. 14 The multiple scattering method has proven to be a powerful and flexible approach for various electron spectroscopies, including x-ray photoemission and x-ray photoelectron diffraction (XPD).…”

Section: Introductionmentioning

confidence: 99%

Real-space multiple scattering method for angle-resolved photoemission and valence-band photoelectron diffraction and its application to Cu(111)

2011

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A computational method is presented for angle-resolved photoemission spectra (ARPES) and photoelectron diffraction (PED) in the ultraviolet regime. The one-step model is employed and both initial valence and final continuum states are calculated using the finite-cluster, real-space multiple scattering method. Thereby the approach is versatile and provides a natural link to core-level PED. The method is applied to the Cu(111) valence band and good agreement with experiment is found for both ARPES spectra and PED patterns. When the PED patterns are integrated over a filled band of a single-orbital symmetry, such as Cu-3d, we show, both numerically and analytically, that the exact theory with delocalized initial states can be replaced by the much simpler, core-level-type theory where the initial states are taken as localized.

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Section: Introductionmentioning

confidence: 99%

Real-space multiple scattering method for angle-resolved photoemission and valence-band photoelectron diffraction and its application to Cu(111)

2011

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“…During the past few years, several theoretical approaches have been used to study transition metal nanoclusters. First principles calculations have been performed on small metal aggregates in order to determine the minimum energy structure and structure/property relationship as a function of cluster size. − Numerical procedures based on genetic algorithms for single and bimetallic structures using atom−atom pair potentials 56 or many-body potentials 56-64 have been used to investigate a broader range of cluster sizes. Focusing on transition metal clusters supported on magnesia surfaces, in the past 10 years, a wealth of results has been collected on the interaction of single metal atoms on the regular and defected sites of the MgO(100) surface. − The extended and localized defected sites of the MgO surface have attracted remarkable attention because of their intrinsic chemical and physical properties 70-84 and because they can act as trapping centers for metal atoms absorbed on the oxide surface. , The results of such calculations have demonstrated that the choice of the model influences the description of the system 86 and that the metal/surface interaction changes primarily as a function of the electronic configuration and the dimensions of the metal species considered.…”

Section: Introductionmentioning

confidence: 99%

The Interaction of Coinage Metal Clusters with the MgO(100) Surface

Barcaro

Fortunelli

2005

J. Chem. Theory Comput.

115

150

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The results of a systematic study of the interaction of small coinage metal clusters (Mn, n = 1-3) and extended deposition (one and two MLs; ML = monolayer) with the regular and locally defected (Fs center and divacancy) neutral MgO(100) surface are presented. The calculations have been performed at the DFT level employing plane waves as a basis set and using a gradient-corrected exchange-correlation functional (PW91). The adhesion energy along the group follows a trend that can be rationalized in terms of the strength and "stickiness" of the metallic bond, electrostatic polarization effects, and chemical interactions. Coinage metal dimers and trimers are absorbed on the regular surface in an upright position with little modification with respect to the gas-phase structure and can easily diffuse from site to site (in the case of trimers, also because of their fluxional character). In the case of extended deposition, the adhesion energy increases when passing from one to two MLs because of a "metal-on-top" stabilization mechanism. Neutral localized defects on the surface such as the Fs center (generated by a missing O atom) and the double vacancy (generated by a missing MgO dimer) act as strong trapping centers for small clusters and remarkably increase the adhesion of metal slabs to the surface in the case of extended deposition. At variance with the Fs center, the double vacancy induces a strong structural and energetic modification of the surrounding oxide lattice, varying also as a function of the metal deposition. A peculiar structural rearrangement consisting of the segregation of the metal slab into "islands" on the surface is observed in the case of one ML Cu and (to a lesser extent) Au.

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“…With regard to clusters, the sizes that have closed‐shell structures are said to be 'magic number' clusters, which are generally unusually stable . The origin of this stability may lie either with the way that the atoms or molecules fit together, or with the way in which the electrons 'fit together'.…”

Section: Resultsmentioning

confidence: 99%

“…2(b With regard to clusters, the sizes that have closed-shell structures are said to be 'magic number' clusters, which are generally unusually stable. [30] The origin of this stability may lie either with the way that the atoms or molecules fit together, or with the way in which the electrons 'fit together'. In positive or negative ion mass spectrometry, the degree of polymerization n is a magic number when the relative intensity of the ion is higher than that of the adjacent peaks.…”

Section: Negative Ion Maldi Spectra Of H 3 Pw 12 O 40mentioning

confidence: 99%

Formation of tungstate‐containing cluster ions by polyoxotungstate anions under matrix‐assisted laser desorption/ionization conditions in the gas phase

Bai

Shu

Song

et al. 2011

Rapid Comm Mass Spectrometry

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The gas-phase studies of transition-metal oxides continue to attract interest as such oxides are being used as catalysts in various oxidation processes. In this paper, singly negatively charged heteropolyoxotungstate and isopolyoxotungstate ion clusters were produced from Keggin-type polyoxotungstates by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS). It was found that the ion series [(PO(3))(WO(3))(n)](-), [(WO(3))(n)](-) and [(OH)(WO(3))(n)](-) were the main fragment ions in the mass spectra and the matrix greatly influenced the resulting cluster ion abundances. [(PO(3))(WO(3))(3)](-), [(WO(3))(3)](-) and [(OH)(WO(3))(4)](-) were the most intense ions in each series when 2-(4-hydroxyphenylazo)benzoic acid was the matrix, whereas [(PO(3))(WO(3))(4)](-), [(WO(3))(6)](-) and [(OH)(WO(3))(4)](-) were the most intense when dithranol (DIT) was the matrix. In addition, a new kind of hybrid ion [W(2)C(14)H(7)O(8)](-) was produced through the reaction of DIT and [(OH)(WO(3))](-) in the plume of the gas phase. These results highlight the utility of the MALDI-FT method for obtaining novel ion clusters and also show the stability of these clusters.

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Progress in Experimental and Theoretical Studies of Clusters

Cited by 20 publications

References 0 publications

Real-space multiple scattering method for angle-resolved photoemission and valence-band photoelectron diffraction and its application to Cu(111)

Real-space multiple scattering method for angle-resolved photoemission and valence-band photoelectron diffraction and its application to Cu(111)

The Interaction of Coinage Metal Clusters with the MgO(100) Surface

Formation of tungstate‐containing cluster ions by polyoxotungstate anions under matrix‐assisted laser desorption/ionization conditions in the gas phase

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