New Geometric Shell Structures

Martin, T. P.; Zimmermann, Uwe; Malinowski, N.; Näher, U.; Frank, S. M.; Tast, F.; Wirth, K.

doi:10.1142/s0218625x96000528

Cited by 9 publications

(11 citation statements)

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“…The groun state of (NaI) 5 and the hexagonal isomers of (NaI) 7 contain some low coordinated ions, in contrast to (NaI) 6 . Both the ground state and the cuboid isomer of (NaI) 9 are more compact than the elongated forms of (NaI) 8 and (NaI) 10 .…”

Section: Binding Energiesmentioning

confidence: 97%

“…But there are other sizes, notably n = 6, 7, 9, 10, 12, 13, 15, for which the clusters, due to their very small sizes, prefer other structures. The magic numbers observed in the mass spectra of large NaI clusters [10] (those clusters are, however, ionized and non-stoichiometric) have been explained as cuboids with the bulk structure. We conclude that the number of atoms in NaI clusters with 15 molecules or less is not yet enough to produce bulk-like clusters.…”

Section: Perturbed Ion Model For Clustersmentioning

confidence: 99%

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Theoretical Study of Small (NaI)_n Clusters

et al. 1997

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A systematic theoretical study of stoichiometric clusters (N aI) n up to n = 15 is performed using the ab initio Perturbed-Ion (PI) model. The structures obtained are compared to previous pair potential results, and observed differences between (N aI) n clusters and previous ab initio results for other alkali halide clusters are discussed. (N aI) n clusters with n up to 15 do not show yet a marked preference for geometries which are fragments of the bulk lattice. Instead, stacks of hexagonal rings or more open structures are obtained as ground structures in clusters with n = 3, 6, 7, 9, 10, 12, 13 and 15, indicating that convergence to bulk structure is not achieved yet at this size range. Low lying isomers which are fragments of the crystal lattice exist, nevertheless, for those cases. The binding energies show that clusters with n = (4), 6, 9 and 12 molecules are specially stable. The binding energy has been decomposed in contributions which allow for an intuitive interpretation. Some electronic properties like ionization potentials and electronic energy levels are also studied.

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Section: Binding Energiesmentioning

confidence: 97%

Section: Perturbed Ion Model For Clustersmentioning

confidence: 99%

Theoretical Study of Small (NaI)_n Clusters

et al. 1997

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“…In particular, exceptionally stable clusters with "magic numbers" of atoms were proved experimentally to exist, using mass spectra analysis. [55][56][57] The densely-packed and self-assembled structures of silica nanoparticles arranged in a regular hexagonal-pentagonal surface lattice, produced by means of spray drying, were re-8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 ported by Onofri et. al.…”

Section: Formation Of Aggregatesmentioning

confidence: 99%

Formation of Highly Ordered Spherical Aggregates from Drying Microdroplets of Colloidal Suspension

et al. 2015

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The formation of highly ordered spherical aggregates of silica nanoparticles by the evaporation of single droplets of an aqueous colloidal suspension levitated (confined) in the electrodynamic quadrupole trap is reported. The transient and final structures formed during droplet evaporation have been deposited on a silicon substrate and then studied with SEM. Various successive stages of the evaporation-driven aggregation of nanoparticles have been identified: formation of the surface layer of nanoparticles, formation of the highly ordered spherical structure, collapse of the spherical surface layer leading to the formation of densely packed spherical aggregates, and rearrangement of the aggregate into the final structure of a stable 3D quasi-crystal. The evaporation-driven aggregation of submicrometer particles in spherical symmetry leads to sizes and morphologies of the transient and final structures significantly different than in the case of aggregation on a substrate. The numerical model presented in the article allows us to predict and visualize the observed aggregation stages and their dynamics and the final aggregates observed with SEM.

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“…Thus, we have analyzed this data in terms of geometrical shell closings. 37,40,68,69 We first attempted to fit the maxima in the mass spectral intensity oscillations to an N 3 dependence. These attempts were not entirely unsuccessful; however, we quickly found that much smaller fitting errors could be obtained if the minima were used as signatures of geometrical shell closings.…”

Section: B Sf 6 Clusters: Evidence For Nonicosahedral Packing At Higmentioning

confidence: 99%

Electron attachment time-of-flight mass spectrometry reveals geometrical shell closings in van der Waals aggregates

Ingólfsson¹,

Wodtke²

2002

The Journal of Chemical Physics

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Articles you may be interested inPhotodissociation of (SO2XH) Van der Waals complexes and clusters (XH = C2H2, C2H4, C2H6) excited at 32 040-32090 cm−1 with formation of HSO2 and X J. Chem. Phys. 140, 054304 (2014); 10.1063/1.4863445Infrared absorption of methanethiol clusters (CH3SH) n , n = 2-5, recorded with a time-of-flight mass spectrometer using IR depletion and VUV ionization A new method to study metastable fragmentation of clusters using a reflectron time-of-flight mass spectrometer Rev.Using electron attachment time-of-flight mass spectrometry, we show how high-precision structural constants of van der Waals aggregates may be obtained for two kinds of homogeneous clusters, (SF 6 ) N and (CO 2 ) N . Furthermore, we obtain size-specific structural information over a wide range of aggregate sizes. Mass spectrometric data are presented regarding the size needed to facilitate the transition from ''cluster packing,'' dominated by nearest-neighbor interactions, to bulk-like packing.For both examples, it appears that the cluster-to-bulk packing transition may occur even for aggregates where the majority of the molecules resides at the surface. The critical size for the cluster-to-bulk transition may be related to the size at which molecules packed as bulk crystals can begin forming nearly spherical shapes. A discussion of the mechanism by which geometrical shell closings are visualized in electron attachment time-of-flight mass spectrometry is also presented. We postulate that these observations reflect the dynamics of electron localization in ordered crystallites with and without defects.

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New Geometric Shell Structures

Cited by 9 publications

References 0 publications

Theoretical Study of Small (NaI)_n Clusters

Theoretical Study of Small (NaI)_n Clusters

Formation of Highly Ordered Spherical Aggregates from Drying Microdroplets of Colloidal Suspension

Electron attachment time-of-flight mass spectrometry reveals geometrical shell closings in van der Waals aggregates

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New Geometric Shell Structures

Cited by 9 publications

References 0 publications

Theoretical Study of Small (NaI)n Clusters

Theoretical Study of Small (NaI)n Clusters

Formation of Highly Ordered Spherical Aggregates from Drying Microdroplets of Colloidal Suspension

Electron attachment time-of-flight mass spectrometry reveals geometrical shell closings in van der Waals aggregates

Contact Info

Product

Resources

About

Theoretical Study of Small (NaI)_n Clusters

Theoretical Study of Small (NaI)_n Clusters