Quantum chemical investigation of support-metal interactions and their influence on chemisorption. 1. The system atomic hydrogen...nickel-silicon dioxide

Haberlandt, Helmut; Ritschl, Friedrich Wilhelm

doi:10.1021/j100240a016

Cited by 9 publications

(1 citation statement)

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“…For insulators and semiconductors dangling bonds at the truncating surface are usually saturated with pseudoatoms. For silica supports the dangling bonds of oxygen and silicon at the surface often are very successfully simply saturated with hydrogen atoms. − The specific model structures for the supported Rh mono- and dicarbonyl adsorbed systems are shown in Figure . The use of three hydrogen atoms to truncate the silica cluster is regarded as a minimal first approximation to a silica structure.…”

Section: Computational Model System and Methodsmentioning

confidence: 99%

Mobility and Clustering of Rh and Ru in Zeolite. Experiment and Theory

et al. 1998

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Ruthenium and rhodium have been atomically dispersed on Na zeolite as shown by the infrared spectra of Rh I (CO) 2 and Ru I (CO) 2 produced upon reduction in a CO atmosphere. Formation of adsorbed CO bridging two Rh(I) surface atoms upon partial removal of adsorbed CO indicates some Rh(I) species can occupy adjacent surface sites contrary to suppositions in most current literature. While Rh(I) surface species seem to be relatively immobile below 100 °C, our data suggest that Rh 0 surface atoms are mobile to some extent. Self-consistent field density functional calculations have been performed for several surface clusters; they indicate that Rh-surface bonds are much weaker for Rh 0 species than for Rh(I) species. These calculations support the proposition that Rh 0 surface species are more mobile than Rh(I) surface species.

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Section: Computational Model System and Methodsmentioning

confidence: 99%

Mobility and Clustering of Rh and Ru in Zeolite. Experiment and Theory

et al. 1998

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Determination of Titanium CNDO Parameters and Application in Cluster Calculations of Different Titanium Compounds

Haberlandt

1986

Physica Status Solidi (b)

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Electronic properties of the titanium clusters Ti, (T,) and Ti6(0,,) are calculated by means of the semiempirical quantum chemical CNDO method. The parameters are derived by adjusting the cluster electronic properties to the corresponding bulk data. Comparing the titanium cluster results with those of small nickel clusters calculated using Blyholder parameters, the same trends are observed as in comparing the bulk properties of both metals. An application of the titanium parameters t o the calculation of the intermetallic compound Ni,Ti gives a further confirmation of their compatibility with the nickel parameters. Using the derived parameters in TiO, cluster calculations leads to a satisfactory description of the electronic properties of this material.Elektronische Eigenschaften der Titan-Cluster Ti,(Td) und Ti6(0,)) werden mit Hilfe der semiempirischen quantenchemischen CNDO-Methode berechnet. Die Parameter der semiempirischen Methode werden bestimmt, indem die elektronischen Eigenschaften der Cluster den entsprechenden Volumeneigenschaften angeglichen werden. Der Vergleich der Reeultate der Titan-Cluster mit denen kleiner Nickel-Cluster, die unter Verwendung von Blyholder-Parametern berechnet wurden, zeigt die gleichen Trends wie der Vergleich der Volumeneigenschaften der beiden Metalle. Eine Anwendung der Titan-Parameter bei der Berechnnng der intermetalliachen Verbindung K3Ti liefert eine weitere Bestatigung fur ihre KompatibilitLt mit den Kickel-Parametern. Die Verwendung der ermittelten Parameter in Clusterrechnungen fur TiO, fiihrt zu einer befriedigenden Beschreibung der elektronischen Eigenschaften dieses Materials.

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