The formation of long carbon chain molecules during laser vaporization of graphite

Heath, J. R.; Zhang, Q.; O’Brien, S.; Curl, R. F.; Kroto, H. W.; Smalley, R. E.

doi:10.1021/ja00236a012

Cited by 235 publications

(115 citation statements)

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“…Since graphite lies adjacent to the region of carbyne in this famous carbon phase diagram [43], a mechanism of transition between the sp 2 and sp phases must exist. The hypothetical "party line" [116] and "ring fusion spiral zipper" mechanism [117] of fullerene formation come close to the ring condensation via carbon chain collapse observed in our QM/MD simulations (see Fig. 5.1).…”

Section: Sp 2 Carbon Network Nucleation: Pentagon First?supporting

confidence: 80%

“…Nearly equal numbers of pentagons and hexagons with a smaller fraction of heptagons are created here. Together, these events resemble closely the party line [116] and ring fusion spiral zipper mechanisms [117]. The carbon chains attached to the nucleus regrow during ring collapse by assimilation of C n chains from the environment (third panel of Fig.…”

Section: Dynamic Self-assembly Of Giant Fullerenesmentioning

confidence: 53%

“…A single stacking mistake would lead to the wrong cage isomer! The "party line" [116] and "ring fusion spiral zipper" mechanism [117] proposed that linear carbon chains and rings would aggregate to form small closed carbon cages with sizes from C 38 , after which the highly strained non-IPR cage would grow by C 2 insertion to C 60 and C 70 . Such a less directed, more "organic" self-assembly mechanism has the advantage that it can explain the striking absence of cluster sizes between and including C 29 and C 37 [57], which would correspond to halfopened carbon basket structures that have many dangling bonds on their edges and are therefore more reactive.…”

Section: Background and Experimental Synthesismentioning

confidence: 99%

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Atomistic Mechanism of Carbon Nanostructure Self-Assembly as Predicted by Nonequilibrium QM/MD Simulations

Irle

Page

Saha

et al. 2012

Practical Aspects of Computational Chemistry II

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We review our quantum chemical molecular dynamics (QM/MD)-based studies of carbon nanostructure formation under nonequilibrium conditions that were conducted over the past 10C years. Fullerene, carbon nanotube, and graphene formation were simulated on the nanosecond time scale, considering experimental conditions as closely as possible. An approximate density functional method was employed to compute energies and gradients on the fly in direct MD simulations, while the simulated systems were pushed away from equilibrium via carbon concentration or temperature gradients. We find that carbon nanostructure formation from feedstock particles involves a phase transition of sp to sp 2 carbon phases, which begins with the formation of Y-junctions, followed by a nucleus consisting of pentagons, hexagons, and heptagons. The dominance of hexagons in the synthesized

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Section: Sp 2 Carbon Network Nucleation: Pentagon First?supporting

confidence: 80%

Section: Dynamic Self-assembly Of Giant Fullerenesmentioning

confidence: 53%

Section: Background and Experimental Synthesismentioning

confidence: 99%

See 1 more Smart Citation

Atomistic Mechanism of Carbon Nanostructure Self-Assembly as Predicted by Nonequilibrium QM/MD Simulations

Irle

Page

Saha

et al. 2012

Practical Aspects of Computational Chemistry II

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“…5) These results in laboratories are useful for the understanding of the rich abundance of the molecules in the interstellar space.…”

Section: Introductionmentioning

confidence: 96%

Time-of-Flight Mass Spectroscopy of Carbon Clusters and Hydrocarbons Produced by Laser Ablation of Graphite under H2 and He Buffer Gas-Formation and Stability of C10 and C2nH2 (n=2-5)-

Kato

Wakabayashi

Momose

et al. 2005

J. Mass Spectrom. Soc. Jpn.

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The products from laser ablated graphite under the flow of H2 and He bu#er gases were analyzed by time-of-flight (TOF) mass spectroscopy in combination with one-photon ionization of an energy of 10.5 eV/ photon. By changing the time interval between the ablation laser pulse and the photoionization laser pulse it was found that the neutral clusters ablated from the graphite have three distinctly di#erent velocities for one and the same value of m/z, which was detected as three separate bunches of TOF mass peaks. The e#ect of changing the time interval was examined extensively. As a result, it was found that the first component that appeared earlier in the ionization region consisted of various bared carbon clusters Cn with nῌ6 and hydrocarbons CnHm with n ῌ4 and mῌ1 through 4 while the second and third components that arrived later were C10 and C2nH2 (nῌ2 through 5) only. This persistence of C10 and C2nH2 at longer delay times was attributed to the robustness of these clusters against collisions occurring in ablated plumes. It was inferred that the robustness is due to the chemical inertness of a monocyclic form for C10 and of a linear polyynic form, H(῎C῎C)n῎H, for C2nH2. In the He bu#er gas heated to 600 K the yield of the third (slowest) component of C10 enhanced drastically, which indicates that thermal collisions in plumes favor the production of this monocycle, which further suggests that the monocycle may play a crucial role in the formation of C60, known as a favored product in hot plumes of ablated graphite. IntroductionCarbon clusters and their hydrogenated derivatives have long attracted attention in molecular spectroscopy, combustion chemistry, material sciences, and interstellar chemistry. 1), 2) Among various experimental techniques, laser ablation of graphite in bu#er gases has been employed to elucidate the structure and reactivity of carbon clusters and their derivatives.3)῎9) It is known that among the derivatives polyynes, H(῎C῎ C) n ῎H, are abundant products in the H 2 bu#er gas as are cyanopolyynes, H(῎C῎C) n ῎C῎N, in CH 3 CN and NH 3 gases. 5) These results in laboratories are useful for the understanding of the rich abundance of the molecules in the interstellar space. 10)῎14)The phenomenon of laser ablation itself is also an interesting subject in non-linear gas dynamics. Thus, ablated emissive products have been investigated by emission spectroscopy 15), 16) and by fast I(image intensifier)῎CCD photography.16) Ions directly produced by ablation also have been studied by mass spectrometry.17)῎20) All these techniques, however, are insensitive to neutral species in the ground electronic ῏

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“…ªÔÔÎÇAEÑÄÂÐËÇ ÔÒÇÍÕÓÑÄ ÖÅÎÇÓÑAEÐÞØ ÙÇÒÑÚÇÍ ÃÞÎÑ ËÐËÙËËÓÑÄÂÐÑ ÒÓÇAEÒÑÎÑÉÇÐËÇÏ ¥ÖÅÎÂÔÂ [11], ÔÑÅÎÂÔÐÑ ÍÑÕÑÓÑÏÖ àÎÇÍÕÓÑÐÐÑÇ ÒÑÅÎÑÜÇÐËÇ AEÎËÐ-ÐÞØ ÖÅÎÇÓÑAEÐÞØ ÏÑÎÇÍÖÎâÓÐÞØ ÙÇÒÑÚÇÍ C n n 5À15 ÏÑÉÇÕ âÄÎâÕßÔâ ËÔÕÑÚÐËÍÑÏ ÏÇÉÊÄÇÊAEÐÞØ AEË××ÖÊÐÞØ ÒÑÎÑÔ [12]. ²ÇÊÖÎßÕÂÕÞ ÓÂÃÑÕÞ ÒÑ ÒÑÎÖÚÇÐËá ÖÅÎÇÓÑAE-ÐÞØ ÏÑÎÇÍÖÎâÓÐÞØ ÙÇÒÑÚÇÍ ÃÞÎË Ä ÍÑÐÙÇ ÍÑÐÙÑÄ ÑÒÖÃÎË-ÍÑÄÂÐÞ [13,14], ÑAEÐÂÍÑ ËÔÔÎÇAEÑÄÂÐËÇ ÔÒÇÍÕÓÑÄ ÖÅÎÇÓÑAE-ÐÞØ ÙÇÒÑÚÇÍ, ÒÑ ÔÖÜÇÔÕÄÖ, Ë ÐÇ ÐÂÚËÐÂÎÑÔß.…”

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Истоки Открытия Фуллеренов: Эксперимент И Гипотеза

Curl¹

1998

Uspekhi Fizicheskikh Nauk

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The formation of long carbon chain molecules during laser vaporization of graphite

Cited by 235 publications

References 1 publication

Atomistic Mechanism of Carbon Nanostructure Self-Assembly as Predicted by Nonequilibrium QM/MD Simulations

Atomistic Mechanism of Carbon Nanostructure Self-Assembly as Predicted by Nonequilibrium QM/MD Simulations

Time-of-Flight Mass Spectroscopy of Carbon Clusters and Hydrocarbons Produced by Laser Ablation of Graphite under H2 and He Buffer Gas-Formation and Stability of C10 and C2nH2 (n=2-5)-

Истоки Открытия Фуллеренов: Эксперимент И Гипотеза

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