The thermal stability and fragmentation of C60 molecule up to 2000 K on the milliseconds time scale

Kolodney, E.; Tsipinyuk, B.; Budrevich, A.

doi:10.1063/1.466755

Cited by 67 publications

(37 citation statements)

References 28 publications

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“…It might be possible that the decline in fullerene mass is due in part to fragmentation of the fullerene molecules in addition to consumption by soot. However, previous studies have shown that C 60 is thermally stable in inert gas up to 1720 K [123,124]. As the temperature in these experiments did not exceed 1300 K, it is unlikely that any unimolecular fragmentation occurred.…”

Section: Discussionmentioning

confidence: 84%

Combustion synthesis of fullerenes and fullerenic nanostructures

Goel

Hebgen

Sande

et al. 2002

Carbon

117

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Fullerenes are molecules comprised entirely of sp 2 -bonded carbon atoms arranged in pentagonal and hexagonal rings to form a hollow, closed-cage structure. Buckyballs, a subset which contains C 60 and C 70 , are single-shell molecules while fullerenic nanostructures can contain many shells and over 300 carbon atoms. Both fullerenes and nanostructures have an array of applications in a wide variety of fields, including medical and consumer products. Fullerenes were discovered in 1985 and were first isolated from the products of a laminar low-pressure premixed benzene/oxygen/argon flame operating at fuel-rich conditions in 1991. Flame studies indicated that fullerene yields depend on operating parameters such as temperature, pressure, residence time, and equivalence ratio. High-resolution transmission electron microscopy (HRTEM) showed that the soot contains nanostructures, including onions and nanotubes.Although flame conditions for forming fullerenes have been identified, the process has not been optimized and many flame environments of potential interest are unstudied. Mechanistic characteristics of fullerene formation remain poorly understood and cost estimation of large-scale production has not been performed. Accordingly, this work focused on: 1) studying fullerene formation in diffusion and premixed flames under new conditions to identify optimal parameters; 2) investigating the reaction of fullerenes with soot; 3) positively identifying C 60 molecules in HRTEM by tethering them to carbon black; and 4) providing a cost estimation for industrial fullerenic soot production.Samples of condensable material from laminar low-pressure benzene/argon/oxygen diffusion flames were collected and analyzed by high-performance liquid chromatography (HPLC) and HRTEM. The highest concentration of fullerenes in a flame was always detected just above the height where the fuel is consumed. The percentage of fullerenes in condensable material increases with decreasing pressure and the fullerene content of flames with similar cold gas velocities shows a strong dependence on length. A shorter flame, resulting from higher dilution or lower pressure, favors the formation of fullerenes rather than soot, exhibited by the lower amount of soot and precursors in such flames. This indicates a stronger correlation of fullerene consumption to soot levels than of fullerene formation to precursor concentration. The maximum flame temperature seems to be of minor importance in formation. The overall highest amount of fullerenes was found for a surprisingly high dilution of fuel with argon. The HRTEM analysis showed an increase of the curvature of the carbon layers, and hence increased fullerenic character, with increasing distance from the burner up to the point of maximum fullerene concentration, after which it decreases, consistent with the HPLC analysis. The soot shows highly ordered regions that appear to have been cells of fullerenic nanostructure formation. The samples also included fullerenic nanostructures such as tubes and sp...

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Section: Discussionmentioning

confidence: 84%

Combustion synthesis of fullerenes and fullerenic nanostructures

Goel

Hebgen

Sande

et al. 2002

Carbon

117

View full text Add to dashboard Cite

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“…Resilience and fragmentation were measured for free molecules excited by excimer laser pulses [5], electron impacts [12,13] or via cluster-surface collision processes [1][2][3][4]. It was found that the energy threshold of fragmentation of C 60 in surface collision is higher than that from electron impacts and laser pulse excitement [1,5,12,13]. A collisional fragmentation threshold of about 45 eV was suggested [5].…”

Section: Introductionmentioning

confidence: 98%

“…This surprising effect stimulated studies of surface scattering mechanisms, both experimentally and by atomic scale computer simulations [5][6][7][8][9][10][11]. Resilience and fragmentation were measured for free molecules excited by excimer laser pulses [5], electron impacts [12,13] or via cluster-surface collision processes [1][2][3][4]. It was found that the energy threshold of fragmentation of C 60 in surface collision is higher than that from electron impacts and laser pulse excitement [1,5,12,13].…”

Section: Introductionmentioning

confidence: 99%

The scattering of low energy C60 on graphite (0001) surfaces

Zhang

Man

Hou

1997

Z Phys D - Atoms, Molecules and Clusters

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The interaction between C 60 molecules with a graphite (0001) surface has been investigated by means of molecular dynamics simulations. The initial energies of the C 60 molecules are 90 and 270 eV, respectively. An empirical model potential suggested by Takai et al. is used to describe the interaction between carbon atoms in the C 60 molecule and between the atoms forming the graphite substrate. The interaction between the C 60 atoms and the graphite atoms is modeled by a suitable Lennard-Jones potential. The resilience of scattered C 60 molecules is observed and its energy distribution is in reasonable agreement with available experimental data, showing no significant dependence of the rebounding translational energy on the incident kinetic energy. The energy partition in the collision has been analyzed in detail and a two-step collision model speculated in the experiments has been discussed based on the simulation results.

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“…1. It consists of the Technion two stage effusive source for superhot C 60 [19][20][21][22][23][24] which is interfaced to the cluster molecular beam machine 18 at the research institute Rijnhuizen of the Stichting voor Fundamenteel Onderzoek der Materie ͑FOM͒. The beam of superhot C 60 can then be irradiated by the tunable IR radiation, emitted from FELIX.…”

Section: Methodsmentioning

confidence: 99%

“…[19][20][21][22][23][24] While the superhot thermal source method can not access the very high internal excitation range above 20 eV, it is presently the only method that can provide a controlled and well defined deposition of essentially pure vibrational thermal energy into C 60 molecules with a well defined canonical distribution. The combination of the thermally tunable superhot C 60 source with the ability of FELIX to resonantly heat thus provides a unique opportunity to study the behavior of an ensemble of extremely vibrationally excited C 60 molecules ͑Ē th = 50-100 eV͒ in a well controlled way.…”

Section: Introductionmentioning

confidence: 99%

Infrared multiphoton ionization of superhot C60: Experiment and model calculations

Bekkerman

Kolodney

Helden

et al. 2006

The Journal of Chemical Physics

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We address, both experimentally and theoretically, the issue of infrared ͑IR͒ resonance enhanced multiphoton ionization ͑IR-REMPI͒ and thermally induced redshifts of IR absorption lines in a very large and highly vibrationally excited molecular system. Isolated superhot C 60 molecules with well defined and variable average vibrational energy in the range of 9 -19 eV, effusing out of a constant flux thermal source, are excited and ionized after the absorption of multiple ͑500-800͒ infrared photons in the 450-1800 cm −1 spectral energy range. Recording the mass-selected ion signal as a function of IR wavelength gives well resolved IR-REMPI spectra, with zero off-resonance background signal. An enhancement of the ion signal of about a factor of 10 is observed when the temperature is increased from 1200 to 1800 K under otherwise identical conditions. A pronounced temperature dependent redshift of some of the IR absorption lines is observed. The observations are found to be in good agreement with a model which is based on the sequential absorption of single photons, always followed by instantaneous vibrational energy redistribution. The mass spectra ͑C 60 + fragmentation pattern͒ are found to be strongly excitation wavelength dependent. Extensive fragmentation down to C 32 + is observed following the absorption of 1350-1400 cm −1 as well as 1500-1530 cm −1 photons while negligible fragmentation is observed when exciting around 520 cm −1 .

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The thermal stability and fragmentation of C60 molecule up to 2000 K on the milliseconds time scale

Cited by 67 publications

References 28 publications

Combustion synthesis of fullerenes and fullerenic nanostructures

Combustion synthesis of fullerenes and fullerenic nanostructures

The scattering of low energy C60 on graphite (0001) surfaces

Infrared multiphoton ionization of superhot C60: Experiment and model calculations

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