Magic and hot giant fullerenes formed inside ion irradiated weakly bound C60 clusters

Zettergren, Henning; Johansson, H.; Schmidt, H. T.; Jensen, Jens; Hvelplund, P.; Tomita, S.; Wang, Yang; Martı́n, Fernando; Alcamı́, Manuel; Manil, B.; Maunoury, L.; Huber, B. A.; Cederquist, H.

doi:10.1063/1.3479584

Cited by 30 publications

(20 citation statements)

References 30 publications

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“…For C 60 À collisions on Ar or Xe, C 59 þ fragments were not observed [20] because penetrating collisions often lead to knockouts of several carbon atoms due to larger nuclear stopping energies (see also Ref. [21]). …”

Section: H Y S I C a L R E V I E W L E T T E R S Week Ending 3 May 2013mentioning

confidence: 99%

Formations of DumbbellC118andC119inside Clusters ofC60
Zettergren
¹
,
Rousseau
²
,
Wang
³

et al. 2013
Phys. Rev. Lett.
Self Cite
62
2
48
0
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We report highly selective covalent bond modifications in collisions between keV alpha particles and van der Waals clusters of C 60 fullerenes. Surprisingly, C 119 þ and C 118 þ are the dominant molecular fusion products. We use molecular dynamics simulations to show that C 59 þ and C 58 þ ions-effectively produced in prompt knockout processes with He 2þ -react rapidly with C 60 to form dumbbell C 119 þ and C 118 þ . Ion impact on molecular clusters in general is expected to lead to efficient secondary reactions of interest for astrophysics. These reactions are different from those induced by photons. DOI: 10.1103/PhysRevLett.110.185501 PACS numbers: 61.48.Àc, 31.15.xv, 36.40.Qv Photodriven intracluster reactions have been observed in clusters of fullerenes [1,2] and in, e.g., clusters of methanol, water, dimethyl ether, and acetic acid molecules [3]. Clusters of fullerenes are of particular interest in this context as C 60 and C 70 recently have been observed in space [4,5] at temperatures indicating that they may reside on grains [4] or are in the solid phase (fullerite) [6]. The question of how fullerenes form in space and elsewhere [7][8][9] is still open and here we report experimental observations on specific very efficient fullerene growth processes inside small pieces of fullerite material. These ion-impact induced growth processes in which so-called dumbbell fullerene systems are formed are inherently different from the ones induced by photons [1,2] for reasons that will be discussed in the following.The lowest energy barrier for formation of covalently bound dumbbell C 120 from two neutral C 60 molecules is roughly one or two electron volts [10]. Thus, two C 60 molecules in their ground states may, in principle, form such a C 120 system when the center-of-mass kinetic energy is larger than this barrier. However, molecular dynamics simulations by Jakowski, Irle, and Morokuma [11] have shown that, in practice, much larger kinetic energies are needed to form dumbbell C 120 (* 60 eV) or single-cage C 120 (*100 eV) efficiently [11]. The reason is that at least one C 60 cage needs to rearrange to form covalent bonds with the other cage on very short, picosecond, time scales. This is highly unlikely in a single encounter at low kinetic energy, as the transferred energy is redistributed over the fullerene molecule and a critical energy needs to be localized in a specific bond in order to break it. On the other hand, the reverse reaction (dissociation) may proceed at much lower energies but after many vibrations and on much longer time scales. For C 60 -C 60 collisions at kinetic energies above 60/100 eV covalent bond formation becomes much more likely but will then also give internally hot dumbbell/single-cage C 120 . Single-cage C 120 will fragment through sequences of C 2 emissions yielding molecular mass distributions with an even number of carbon atoms [1] as C 2 loss is the lowest-energy dissociation channel at about 10 eV. The dumbbell C 120 ! C 60 þ C 60 dissociation energy is only a couple of eV [1...

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Section: H Y S I C a L R E V I E W L E T T E R S Week Ending 3 May 2013mentioning

confidence: 99%

Formations of DumbbellC118andC119inside Clusters ofC60
Zettergren
¹
,
Rousseau
²
,
Wang
³

et al. 2013
Phys. Rev. Lett.
Self Cite
62
2
48
0
View full text Add to dashboard Cite

show abstract

“…The subsequent release of C 2 molecules may then produce CCH through reactions with H 2 . There is a substantial activation energy for ejection of C 2 from C 60 (e.g., Zettergren et al 2010;Micelotta et al 2012), but at sufficiently high stellar temperatures, this energy barrier could be overcome. Clearly H 2 has to be present for CCH to form, however, via the proposed process.…”

Section: A Connection To C 60 ?mentioning

confidence: 99%

New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C₆₀?

Schmidt

Ziurys

2017

ApJ

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New detections of CCH have been made toward nine planetary nebulae (PNe), including K4-47, K3-58, K3-17, M3-28, and M4-14. Measurements of the N = 1 → 0 and N = 3 → 2 transitions of this radical near 87 and 262 GHz were carried out using the new 12 m and the Sub-Millimeter Telescope (SMT) of the Arizona Radio Observatory (ARO). The presence of fine and/or hyperfine structure in the spectra aided in the identification. CCH was not observed in two PNe which are sources of C 60 . The planetary nebulae with positive detections represent a wide range of ages and morphologies, and all had previously been observed in HCN and HNC. Column densities for CCH in the PNe, determined from radiative transfer modeling, were N tot (CCH) ∼ 0.2-3.3 × 10 15 cm −2 , corresponding to fractional abundances with respect to H 2 of f ∼ 0.2-47 × 10 −7 . The abundance of CCH was found to not vary significantly with kinematic age across a time span of ∼10,000 years, in contrast to predictions of chemical models. CCH appears to be a fairly common constituent of PNe that are carbon-rich, and its distribution may anti-correlate with that of C 60 . These results suggest that CCH may be a product of C 60 photodestruction, which is known to create C 2 units. The molecule may subsequently survive the PN stage and populate diffuse clouds. The distinct, double-horned line profiles for CCH observed in K3-45 and M3-28 indicate the possible presence of a bipolar flow oriented at least partially toward the line of sight.

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“…The result is a large, vibrationally-excited fullerenic cage that shrinks down to the stable molecules C 60 and C 70 through emission of C 2 groups. The energy barrier for C 2 ejection from C 60 , higher than that for the neighbours C 58 and C 62 [8] prevents further dissociation.…”

Section: From Hac Nanoparticles To C 60 In Spacementioning

confidence: 99%

The Circle of Dust: From Nanoparticles to Macromolecules and Beyond

Micelotta¹,

Jones²,

Bocchio³

et al. 2014

Proceedings of the Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments — PoS(LCDU2013)

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There is increasing observational evidence that a non-negligible fraction of the cosmic carbon is locked up into macromolecules and nanoparticles. Carbonaceous nanoparticles and Hydrogenated Amorphous Carbon (HAC) nanoparticles represent one of the main components of interstellar dust. HAC nanoparticles have been proposed as a viable carrier for the Unidentified InfraRed (UIR) bands, which dominate the mid-infrared spectrum of almost any astronomical object. Fullerene molecules C 60 and C 70 have been detected in various circumstellar and interstellar environments. We present some of our recent results about the evolution of such carbonaceous structures and the possible connections between each other. We show how photo-processing of HAC nanoparticles can lead to the formation of C 60 and C 70 in space. There the low density of the gas precludes the formation of fullerene materials following known vaporization or combustion synthesis routes, even on astronomical timescales. We then discuss the processing of small hydrocarbon dust by energetic ions and electrons under extreme conditions, e.g., in shocked regions. Finally, we derive the astrophysical implications of such processing in terms of the observed emission.

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Magic and hot giant fullerenes formed inside ion irradiated weakly bound C60 clusters

Cited by 30 publications

References 30 publications

Formations of DumbbellC118andC119inside Clusters ofC60
Zettergren
¹
,
Rousseau
²
,
Wang
³

et al. 2013
Phys. Rev. Lett.
Self Cite
62
2
48
0
View full text Add to dashboard Cite

Formations of DumbbellC118andC119inside Clusters ofC60
Zettergren
¹
,
Rousseau
²
,
Wang
³

et al. 2013
Phys. Rev. Lett.
Self Cite
62
2
48
0
View full text Add to dashboard Cite

New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C₆₀?

The Circle of Dust: From Nanoparticles to Macromolecules and Beyond

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Magic and hot giant fullerenes formed inside ion irradiated weakly bound C60 clusters

Cited by 30 publications

References 30 publications

Formations of DumbbellC118andC119inside Clusters ofC60Zettergren1, Rousseau2, Wang3 et al. 2013Phys. Rev. Lett.Self Cite622480View full textAdd to dashboardCite

Formations of DumbbellC118andC119inside Clusters ofC60Zettergren1, Rousseau2, Wang3 et al. 2013Phys. Rev. Lett.Self Cite622480View full textAdd to dashboardCite

New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C60?

The Circle of Dust: From Nanoparticles to Macromolecules and Beyond

Contact Info

Product

Resources

About

Formations of DumbbellC118andC119inside Clusters ofC60
Zettergren
¹
,
Rousseau
²
,
Wang
³

et al. 2013
Phys. Rev. Lett.
Self Cite
62
2
48
0
View full text Add to dashboard Cite

Formations of DumbbellC118andC119inside Clusters ofC60
Zettergren
¹
,
Rousseau
²
,
Wang
³

et al. 2013
Phys. Rev. Lett.
Self Cite
62
2
48
0
View full text Add to dashboard Cite

New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C₆₀?