Experimental evidence for the formation of fullerenes by collisional heating of carbon rings in the gas phase

Helden, Gert von; Gotts, Nigel G.; Bowers, Michael T.

doi:10.1038/363060a0

Cited by 413 publications

(267 citation statements)

References 23 publications

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“…near-thermal equilibrium conditions, can be drawn for those TIED cases that require a mixture of lowest energy isomers to optimally fit the measurements (Au − 12 , Au − 18 and Au + 20 ). Note however, that equilibrium isomer distributions are not always observed in cluster experiments: carbon clusters made by laser vaporization of graphite, for example, coexist in several non-interconverting isomeric forms, such as chains, rings and cages, and can be completely annealed into the most stable form upon injection into the drift cell (Von Helden et al 1993a). Carbon clusters have much higher binding energies and interconversion barriers than gold clusters do.…”

Section: (C) Isomer Distributions Interconversion Kinetics and Thermmentioning

confidence: 99%

Determining the size-dependent structure of ligand-free gold-cluster ions

Schooss

Weis

Hampe

et al. 2010

Phil. Trans. R. Soc. A.

112

108

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Ligand-free metal clusters can be prepared over a wide size range, but only in comparatively small amounts. Determining their size-dependent properties has therefore required the development of experimental methods that allow characterization of sample sizes comprising only a few thousand mass-selected particles under well-defined collisionfree conditions. In this review, we describe the application of these methods to the geometric structural determination of Au + n and Au − n with n = 3-20. Geometries were assigned by comparing experimental data, primarily from ion-mobility spectrometry and trapped ion electron diffraction, to structural models from quantum chemical calculations.

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Section: (C) Isomer Distributions Interconversion Kinetics and Thermmentioning

confidence: 99%

Determining the size-dependent structure of ligand-free gold-cluster ions

Schooss

Weis

Hampe

et al. 2010

Phil. Trans. R. Soc. A.

112

108

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“…A difficulty in current experiments (Hunter et al 1993, von Helden et al 1993a is that the products can only be detected on time scales of µs, long after many of the important formation steps have been completed. Consequently, it is necessary to use first principles quantum mechanical theory to determine these initial states; however, the experiments serve to provide boundary conditions that severely limit the possibilities, making the use of first principles theory practicable.…”

Section: Introductionmentioning

confidence: 99%

QM(DFT) and MD studies on formation mechanisms of C₆₀fullerenes

et al. 2000

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Abstract. One of the most puzzling aspects of fullerenes is how such complicated symmetric molecules are formed from a gas of atomic carbons, namely, the atomistic or chemical mechanisms. Are the atoms added one by one or as molecules (C 2 , C 3 )? Is there a critical nucleus beyond which formation proceeds at gas kinetic rates? What determines the balance between forming buckyballs, buckytubes, graphite and soot? The answer to these questions is extremely important in manipulating the systems to achieve particular products. A difficulty in current experiments is that the products can only be detected on time scales of microseconds long after many of the important formation steps have been completed. Consequently, it is necessary to use simulations, quantum mechanics and molecular dynamics, to determine these initial states. Experiments serve to provide the boundary conditions that severely limit the possibilities. Using quantum mechanical methods (density functional theory (DFT)) we derived a force field (MSXX FF) to describe one-dimensional (rings) and two-dimensional (fullerene) carbon molecules. Combining DFT with the MSXX FF, we calculated the energetics for the ring fusion spiral zipper (RFSZ) mechanism for formation of C 60 fullerenes. Our results shows that the RFSZ mechanism is consistent with the quantum mechanics (with a slight modification for some of the intermediates).

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“…It is generally agreed that the most stable carbon isomers should be chains and rings for up to N~20 -30 atoms, and closed single-wall fullerenes for tens to hundreds of atoms [9,[11][12][13]. Only beyond several hundred atoms should one observe a transition to spherical multi-layer "onions" [14,15].…”

Section: Formation Mechanismmentioning

confidence: 99%

Self-assembly and electronic structure of bundled single- and multi-wall nanotubes

Tománek¹

1998

AIP Conference Proceedings

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A bstract. Detailed growth mechanism of single-wall nanotube bundles and of multiwall nanotubes of carbon is investigated using ab initio and parametrized calculations. Our results show that single-wall tubes grow only in presence of a catalyst, whereas multi-wall tubes, stabilized at the growing edge by a covalent "lip-lip" interaction, may form in a pure carbon atmosphere. The individual tubes in these systems are likely to exhibit a low-frequency twisting motion. The weak, partly anisotropic inter-wall interaction, present in single-wall nanotube bundles and in multi-wall nanotubes, may cause significant changes in the density of states near the Fermi level.

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Experimental evidence for the formation of fullerenes by collisional heating of carbon rings in the gas phase

Cited by 413 publications

References 23 publications

Determining the size-dependent structure of ligand-free gold-cluster ions

Determining the size-dependent structure of ligand-free gold-cluster ions

QM(DFT) and MD studies on formation mechanisms of C₆₀fullerenes

Self-assembly and electronic structure of bundled single- and multi-wall nanotubes

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Experimental evidence for the formation of fullerenes by collisional heating of carbon rings in the gas phase

Cited by 413 publications

References 23 publications

Determining the size-dependent structure of ligand-free gold-cluster ions

Determining the size-dependent structure of ligand-free gold-cluster ions

QM(DFT) and MD studies on formation mechanisms of C60fullerenes

Self-assembly and electronic structure of bundled single- and multi-wall nanotubes

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QM(DFT) and MD studies on formation mechanisms of C₆₀fullerenes