Chemisorption of ethylene on Si5+ cluster ions. A theoretical study

Woeller, Markus; Mühlhäuser, Max; Peyerimhoff, Sigrid D.; Grein, Friedrich

doi:10.1016/s0009-2614(98)00359-5

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…This prevented Jahn-Teller distortion to lower symmetries ͑in either LDA or PWB͒: C 2v for Si 5 ϩ and Si 7 ϩ vs D 3h for Si 5 and D 5h for Si 7 , and C s for Si 10 ϩ vs C 3v for Si 10 . Kishi et al 52 and Grein and co-workers 53 have recently found the same distortions for Si 5 ϩ and Si 7 ϩ using ab initio and density functional methods. So, the global minima for these sizes are actually deeper than those given in Ref.…”

Section: B Correction Of Cationsmentioning

confidence: 65%

Modeling ionic mobilities by scattering on electronic density isosurfaces: Application to silicon cluster anions

Shvartsburg

Liu

Jarrold

et al. 2000

The Journal of Chemical Physics

137

215

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We have developed a new formalism to evaluate the gas-phase mobility of an ion based on elastic scattering on an electronic density isosurface ͑SEDI͒. In this method, the ion is represented by a surface of arbitrary shape defined as a set of points in space where the total electron density assumes a certain value. This value is the only adjustable parameter in the model. Conceptually, this treatment emulates the interaction between a drifting ion and the buffer gas atoms closer than the previously described methods, the exact hard spheres scattering ͑EHSS͒ model and trajectory calculations, where the scattering occurs in potentials centered on the nuclei. We have employed EHSS, trajectory calculations, and SEDI to compute the room temperature mobilities for low-energy isomers of Si n (nр20) cations and anions optimized by density functional theory ͑DFT͒ in the local density approximation and generalized gradient approximation. The results produced by SEDI are in excellent agreement with the measurements for both charge states, while other methods can fit the mobilities for cations only. Using SEDI, we have confirmed the structural differences between Si n ϩ and Si n Ϫ predicted by DFT calculations, including the major rearrangements for nϭ9, 15, 16, and 18. We have also assigned the multiple isomers observed in recent high-resolution mobility measurements for Si n ϩ with nϭ17-19, some of them to near-spherical cage-like geometries.

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Section: B Correction Of Cationsmentioning

confidence: 65%

Modeling ionic mobilities by scattering on electronic density isosurfaces: Application to silicon cluster anions

Shvartsburg

Liu

Jarrold

et al. 2000

The Journal of Chemical Physics

137

215

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“…The measured cluster mobilities [2] show that the charge state affects the relative stability of the isomers. Structural changes caused by charging neutral silicon clusters have previously been examined in other studies [11,[21][22][23][24]. Except for n ¼ 6; 8; 12; and 13 the ground-state structures remain identical to those of the neutrals, with little relaxation.…”

Section: Methods and Optimization Techniquesmentioning

confidence: 90%

Shape transition of medium‐sized neutral silicon clusters

Sieck¹,

Frauenheim

Jackson

2003

Physica Status Solidi (b)

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Addressing the shape transition of silicon clusters, indicated by mobility experiments on silicon cluster cations with 24 to 30 atoms, we investigate the structure of low energy neutral silicon clusters with 25, 29, and 35 atoms within a density-functional based tight-binding approach. Since there is strong evidence for several nearly degenerate low-energy isomers for clusters of this size, we perform an extensive, but limited global search with Simulated Annealing and statistically analyze for each cluster size the 100 clusters with the lowest energy. We find different dominant shapes in the set of low energy clusters for each size. For neutral silicon clusters with 25 atoms, both prolate and spherical structures with low cohesive energies exist. For clusters containing 29 or 35 atoms, the low-energy isomers exhibit a spherical shape. For each cluster size several stable isomers with similar shapes, and hence similar mobilities, but different bonding patterns exist. The most stable 25 atom cluster resulting from our global search has the lowest energy within DFT-GGA known so far. Finally, we investigate the transition to diamond-like bonding patterns expected for larger silicon clusters. Clusters with up to 239 atoms resemble amorphous silicon rather than the diamond structure and contain several highly coordinated atoms.

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“…The geometries for Si n ϩ with nр7 have been extensively optimized. 4,62,63 It has been found that, except for n ϭ6, the structures remain identical to those of the neutrals. Si 6 rearranges upon charging into a lower-symmetry C 2v isomer.…”

Section: Introductionmentioning

confidence: 92%

Ionization of medium-sized silicon clusters and the geometries of the cations

Liu

Pan

et al. 1998

The Journal of Chemical Physics

173

193

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Articles you may be interested inThe effect of ionization on the global minima of small and medium sized silicon and magnesium clusters Energies and spatial features for the rotationless bound states of He 3 + 4 ( Σ g + 2 ) : A cationic core from helium cluster ionization One-photon mass-analyzed threshold ionization spectroscopy of 1,3,5-trifluorobenzene: The Jahn-Teller effect and vibrational analysis for the molecular cation in the ground electronic state Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of hexafluorobenzene: The Jahn-Teller effect and vibrational analysis Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of p -, m -, and o -difluorobenzenes. Ionization energies and vibrational frequencies and structures of the cationsWe have performed a systematic ground state geometry search for the singly charged Si n cations in the medium-size range (nр20) using density functional theory in the local density approximation ͑LDA͒ and generalized gradient approximation ͑GGA͒. The structures resulting for nр18 generally follow the prolate ''stacked Si 9 tricapped trigonal prism'' pattern recently established for the lowest energy geometries of neutral silicon clusters in this size range. However, the global minima of Si n and Si n ϩ for nϭ6, 8, 11, 12, and 13 differ significantly in their details. For Si 19 and Si 20 neutrals and cations, GGA renders the prolate stacks practically isoenergetic with the near-spherical structures that are global minima in LDA. The mobilities in He gas evaluated for all lowest energy Si n ϩ geometries using the trajectory method agree with the experiment, except for nϭ18 where the second lowest isomer fits the measurements. The effect of gradient corrections for either the neutral or cationic clusters is subtle, but their inclusion proves to be critical for obtaining agreement with the mobility measurements in the nϭ15-20 range. We have also determined ionization potentials for our Si n neutral geometries and found that all experimental size-dependent trends are reproduced for nр19. This particularly supports our structural assignments for Si 9 , Si 11 , Si 12 , and Si 17 neutrals. The good overall agreement between the measured and calculated properties supports the elucidation of the ''prolate'' family of silicon clusters as stacks of trigonal prisms.

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Chemisorption of ethylene on Si5+ cluster ions. A theoretical study

Cited by 5 publications

References 10 publications

Modeling ionic mobilities by scattering on electronic density isosurfaces: Application to silicon cluster anions

Modeling ionic mobilities by scattering on electronic density isosurfaces: Application to silicon cluster anions

Shape transition of medium‐sized neutral silicon clusters

Ionization of medium-sized silicon clusters and the geometries of the cations

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