Magic numbers in CN+ and CN− abundance distributions

Hahn, M. Y.; Honea, Eric C.; Paguia, A. J.; Schriver, K. E.; Camarena, A. M.; Whetten, Robert L.

doi:10.1016/0009-2614(86)80415-8

Cited by 60 publications

(4 citation statements)

References 16 publications

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“…Following our study presented herein, another important question arises about the relative stability between the neutral and cation Met-Cars: will we observe a similar mass distribution change as in Figure if we study the cation clusters under the same cluster source conditions? Similar questions had been discussed in the studies of the stability of C 60 as cations and anions, − where it was finally proven experimentally that, depending on the charge state, the cluster source has different optimum conditions for abundant production of C 60 . Based on this intriguing result for C 60 , studies to answer related questions for Met-Cars are to be conducted next.…”

Section: Resultsmentioning

confidence: 70%

Titanium−Carbon Clusters: New Evidence for High Stability of Neutral Met-Cars

Sakurai

Castleman

1997

J. Phys. Chem. A

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The objective of the present study is to establish whether the neutral titanium metallocarbohedrene cluster (Met-Car), Ti8C12, has a high stability as does its cation counterpart. In this investigation, neutral titanium−carbon clusters were studied by mass spectrometry following near-threshold photoionization. We found that copious quantities of the neutral Met-Cars are produced under certain conditions where the power of the vaporization laser for cluster formation is sufficiently high. Under these conditions, a prominent peak corresponding to Ti8C12 is detected even at very low fluences of the ionization laser employed to acquire single-photon ionization conditions. The present study provides clear evidence to lay to rest the question raised by Brock and Duncan in their recent paper (J. Phys. Chem. 1996, 100, 5654), whether the neutral Met-Cars are stable or not.

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Section: Resultsmentioning

confidence: 70%

Titanium−Carbon Clusters: New Evidence for High Stability of Neutral Met-Cars

Sakurai

Castleman

1997

J. Phys. Chem. A

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“…[26] Other abundant fullerenes such as C 36 , C 50 , C 76 , C 78 , and C 84 and so on should be also mentioned (see, for example, Refs. [3,26,27]). The selforganization paradigm does not give any advantage to certain fullerene isomers and even to certain fullerene sizes.…”

Section: Self-organization Paradigm Of Fullerene Formationmentioning

confidence: 99%

“…Moreover, the selforganization paradigm does not give any preference to formation of initial fullerene shells consisting of an even number of atoms relative to shells consisting of an odd number of atoms. For example, mass spectra of carbon clusters produced from graphite by laser ablation [27] and using the pulsed microplasma cluster source [28] show that the fraction of clusters with an odd number of atoms is only several times less than the fraction of even clusters. MD simulations of fullerene formation as a result of self-organization of initially chaotic carbon systems also demonstrate that formation of both even and odd fullerenes takes place.…”

Section: Self-organization Paradigm Of Fullerene Formationmentioning

confidence: 99%

Multiscale modeling strategy to solve fullerene formation mystery

Popov

Lebedeva

Вырко

et al. 2021

Fullerenes, Nanotubes and Carbon Nanostructures

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Since fullerene formation occurs under conditions where direct observation of atomic-scale reactions is not possible, modeling is the only way to reveal atomistic mechanisms which can lead to selection of abundant fullerene isomers (like C 60 -I h ). In the present paper we review the results obtained for different atomistic mechanisms by various modeling techniques. Although it seems that atomic-scale processes related to odd fullerenes (such as growth by consecutive insertions of single carbon atoms and rearrangements of the sp 2 structure promoted by extra sp atoms) provide the main contribution to selection of abundant isomers, at the moment there is no conclusive evidence in favor of any particular atomistic mechanism. Thus, the following multiscale modeling strategy to solve the mystery of the high yield of abundant fullerene isomers is suggested. On the one hand, sets of reactions between fullerene isomers can be described using theoretical graph techniques. On the other hand, reaction schemes can be revealed by classical molecular dynamics simulations with subsequent refinement of the activation barriers by ab initio calculations. Based on the reaction sets with the reaction probabilities derived in this way, the different atomistic mechanisms of abundant fullerene isomer selection can be compared using kinetic models.

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“…Carbon clusters in the small size range have been described in many mass spectrometry experiments. − Depending on the details of the experiment and the ionization method employed, certain cluster ions stand out as more prominent, and these have been speculated to be more stable based on their enhanced abundances. Of course the most famous example of this occurs in the larger cluster sizes for C 60 and the higher fullerenes. − , Unfortunately, it is now understood that many of the earlier results on smaller clusters were misleading because of the variation of the ionization potential with cluster size and fragmentation in the ionization processes employed.…”

Section: Introductionmentioning

confidence: 99%

Ionization Thresholds of Small Carbon Clusters: Tunable VUV Experiments and Theory

et al. 2007

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Small carbon clusters (C n , n=2-15) are produced in a molecular beam by pulsed laser vaporization and studied with vacuum ultraviolet (VUV) photoionization mass spectrometry.The required VUV radiation in the 8-12 eV range is provided by the Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory. Mass spectra at various ionization energies reveal the qualitative relative abundances of the neutral carbon clusters produced. By far the most abundant species is C 3 . Using the tunability of the ALS, ionization threshold spectra are recorded for the clusters up to 15 atoms in size. The ionization thresholds are compared to those measured previously with charge transfer bracketing methods. To interpret the ionization thresholds for different cluster sizes, new ab initio calculations are carried out on the clusters for n=4-10. Geometric structures are optimized at the CCSD(T) level with cc-pVTZ (or cc-pVDZ) basis sets, and focal point extrapolations are applied to both neutral and cation species to 2 determine adiabatic and vertical ionization potentials. The comparison of computed and measured ionization potentials makes it possible to investigate the isomeric structures of the neutral clusters produced in this experiment. The measurements are inconclusive for the n=4-6 species because of unquenched excited electronic states. However, the data provide evidence for the prominence of linear structures for the n = 7, 9, 11, 13 species and the presence of cyclic C 10 .

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Magic numbers in CN+ and CN− abundance distributions

Cited by 60 publications

References 16 publications

Titanium−Carbon Clusters: New Evidence for High Stability of Neutral Met-Cars

Titanium−Carbon Clusters: New Evidence for High Stability of Neutral Met-Cars

Multiscale modeling strategy to solve fullerene formation mystery

Ionization Thresholds of Small Carbon Clusters: Tunable VUV Experiments and Theory

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