From Gas Phase Clusters to Nanomaterials: An Overview of Theoretical Insights

doi:10.5012/bkcs.2003.24.6.757

Cited by 22 publications

(6 citation statements)

References 136 publications

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“…In Table , we have compared the calculated geometrical structures and dissociation energies of NaOH and KOH with the experimental data. − , The B3LYP/MP2/CCSD(T) M−O distances for M = Na and K are 1.96/1.99/1.99 and 2.25/2.26/2.26 Å, respectively, in reasonable agreement with the experimental values (1.95 and 2.20 Å) 15,16,31 and the previous calculated results . The OH - distance is 0.95/0.96/0.96 Å. NaOH has a linear structure (180°), whereas KOH has an almost linear structure (178°).…”

Section: Resultssupporting

confidence: 79%

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Hydration Phenomena of Sodium and Potassium Hydroxides by Water Molecules

et al. 2006

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The hydrated structures, dissociation energies, thermodynamic quantities, infrared spectra, and electronic properties of alkali-metal hydroxides (MOH, M = Na and K) hydrated by up to six water molecules [MOH(H(2)O)(n=1-6)], are investigated by using the density functional theory and Møller-Plesset second-order perturbation theory. Further accurate analysis based on the coupled cluster theory with singles, doubles, and perturbative triples excitations is more consistent with the MP2 results. NaOH shows a peculiar trend in dissociation: it begins to form a partially dissociated structure for n = 3, and it dissociates for n = 4 and 6, whereas it is undissociated for n = 5. However, for n = 5, the dissociated structure is nearly isoenergetic to the undissociated structure. For KOH, it begins to show partial dissociation for n = 5, and complete dissociation for n = 6.

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Section: Resultssupporting

confidence: 79%

“…Thus, for mimicking various medicinal and environmental mechanisms, the understanding of mechanistic actions of alkali-metal ions would be highly beneficial. Indeed, the alkali-metal ion recognition by receptors has been an important subject for biosensing …”

Section: Introductionmentioning

confidence: 99%

Hydration Phenomena of Sodium and Potassium Hydroxides by Water Molecules

et al. 2006

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“…Apart from providing the most consistent theoretical comparison of cation−water interactions involving various kinds of monovalent cations, we have also provided a detailed description of the magnitudes of the interaction energy components of the cation−water interactions. This, we believe, would enable one to obtain a thorough understanding of ion-specific recognition and its utility in designing novel molecular systems and functional materials . It would also promote the development of new potential models to describe ion−water interactions.…”

Section: Discussionmentioning

confidence: 88%

Insights into the Structures, Energetics, and Vibrations of Monovalent Cation−(Water)₁_-₆Clusters

et al. 2004

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This study details the interactions prevailing in aqueous clusters of monovalent alkali metal, ammonium, and hydronium cations. The calculations involve a detailed evaluation of the structures, thermodynamic energies, and IR spectra of several plausible conformers of M + ‚(H 2 O) 1-6 (M ) Li, Na, K, Rb, Cs, NH 4 , H 3 O) clusters at the second-order Møller-Plesset (MP2) and density functional levels of theory. A detailed decomposition of the interaction energies has been carried out for complexes involving one or two water molecules using symmetry adapted perturbation theory. Some of the salient insights on the structures include the emergence of the second solvent shell even before the realization of the maximal coordination number of the cation. This effect was more pronounced in clusters involving the larger cations. The quantitative estimates of various components of the interaction energy indicate the predominance of electrostatic energies in the binding of these cations to water molecules. Interestingly, for all the hydrated alkali metal cation complexes, the contribution of electrostatic energy is almost the same as the total attractive interaction energy, whereas the sum of the induction and dispersion energies are almost canceled out by exchange-repulsion energy. However, the contribution of dispersion energies slowly starts increasing as the size of the cation increases and is quite substantial in case of the Cs + complexes. In the organic cations, the dispersion energies become significant, though not comparable to the electrostatic energies. In addition to the evaluation of the harmonic frequencies of -OH stretching mode of all the structures, the anharmonic frequencies were evaluated for the smaller clusters. As the size of the cation and the size of the water cluster increases, the red shifts associated with the -OH stretching mode progressively become larger for the alkali metal cation containing complexes. For the organic cation (NH 4 + , H 3 O + ) containing complexes, an opposite trend is observed. Compared to the isolated water monomer, the ratio of the infrared intensities of the asymmetric and symmetric -OH stretching modes is very small. However, this ratio progressively becomes larger as the size of the cation increases. † Part of the special issue "Fritz Schaefer Festschrift".

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“…We believe that our work will stimulate further investigation on the mechanism of alloy formation in binary alloys as well as the ductility in making 1-D nanowires and 2-D thin films in other interesting systems, which would open a new branch in chemistry.…”

Section: Discussionmentioning

confidence: 90%

“…The intense quest toward the design of novel nanofunctional materials (such as quantum dot, nanoclusters, and nanowires) has motivated several studies on small-sized metallic clusters (either with or without interaction with ligands). − The goal of most of these studies is to examine the modulation of the physical properties as a result of a decrease in the size. The dominance of quantum effects in such small dimensions leads to the emergence of several interesting characteristics.…”

Section: Introductionmentioning

confidence: 99%

Geometrical and Electronic Structures of Gold, Silver, and Gold−Silver Binary Clusters: Origins of Ductility of Gold and Gold−Silver Alloy Formation

et al. 2003

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The structures of pure gold and silver clusters (Au k , Ag k , k ) 1-13) and neutral and anionic gold-silver binary clusters (Au m Ag n , 2 e k ) m + n e 7) have been investigated by using density functional theory (DFT) with generalized gradient approximation (GGA) and high level ab initio calculations including coupled cluster theory with relativistic ab initio pseudopotentials. Pure Au k clusters favor 2-D planar configurations, while pure Ag k clusters favor 3-D structures. In the case of Au, the valence orbital energies of 5d are close to that of 6s. This allows the hybridization of 6s and 5d orbitals in favor of planar structures of Au k clusters. Even 1-D linear structures show reasonable stability as local minima (or as global minima in a few small anionic clusters). This explains the ductility of gold. On the other hand, the Ag-4d orbital has a much lower energy than the 5s. This prevents hybridization, and so the coordination number (Nc) of Ag in Ag k tends to be large in s-like spherical 3-D coordination in contrast to that of Au in Au k which tends to be small in 1-D or 2-D coordination. This trend is critical in determining the cluster structures. The calculated electronic properties and dissociation energy of both pure and binary clusters are in good agreement with the available experimental data. Since the Ag-5s orbital is much higher in energy than the Au-6s orbital energy, the partial charge transfer from Au to Ag takes place in gold-silver binary clusters. Au atoms tend to be negatively charged, while Ag atoms tend to be positively charged. Combined with the trend that Au atoms favor the surface, edges, or vertices with smaller Nc, the outer part of the cluster tends to be negatively charged, while Ag atoms favor the inside with larger Nc, and so the inner part tends to be positively charged. The partial charge transfer in the binary system results in electrostatic energy gain for the binary Au m Ag n cluster over pure Au k and Ag k clusters, which is responsible for the formation of alloys. In a neutral alloy, the equivalent mixing is favored, and the even numbered k tends to be more stable due to the electron spin pairing, whereas in an anionic alloy the odd numbered k tends to be more stable.

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From Gas Phase Clusters to Nanomaterials: An Overview of Theoretical Insights

Cited by 22 publications

References 136 publications

Hydration Phenomena of Sodium and Potassium Hydroxides by Water Molecules

Hydration Phenomena of Sodium and Potassium Hydroxides by Water Molecules

Insights into the Structures, Energetics, and Vibrations of Monovalent Cation−(Water)₁_-₆Clusters

Geometrical and Electronic Structures of Gold, Silver, and Gold−Silver Binary Clusters: Origins of Ductility of Gold and Gold−Silver Alloy Formation

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From Gas Phase Clusters to Nanomaterials: An Overview of Theoretical Insights

Cited by 22 publications

References 136 publications

Hydration Phenomena of Sodium and Potassium Hydroxides by Water Molecules

Hydration Phenomena of Sodium and Potassium Hydroxides by Water Molecules

Insights into the Structures, Energetics, and Vibrations of Monovalent Cation−(Water)1-6Clusters

Geometrical and Electronic Structures of Gold, Silver, and Gold−Silver Binary Clusters: Origins of Ductility of Gold and Gold−Silver Alloy Formation

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Insights into the Structures, Energetics, and Vibrations of Monovalent Cation−(Water)₁_-₆Clusters