The C
            <sub>7</sub>
            Cluster: Structure and Infrared Frequencies

Heath, J. R.; Sheeks, R.; Cooksy, Andrew L.; Saykally, Richard J.

doi:10.1126/science.11538081

Cited by 70 publications

(16 citation statements)

References 20 publications

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“…In addition, lowlying cyclic structures for the C 4 , C^, and C g clusters are also predicted (22)(23)(24)(25). Much of this theory for the linear structures has been confirmed by high-resolution infrared spectroscopy (13)(14)(15)(26)(27)(28)(29)(30)(31)(32)(33), and experimental data that have been applied to the determination of the structures of triplet linear C 4 and singlet linear C 9 are presented in Figures 4 and 5, respectively. Molecular parameters derived from fits (see the section "Energy Level Expressions Used for Determination of Carbon-Cluster Molecular Parameters" for details) to this and similar spectra for other linear chains are presented in Table I.…”

Section: ) Which Quickly Proceed Through Step 4 To Produce the Fulmentioning

confidence: 72%

Synthesis of C₆₀ from Small Carbon Clusters

Heath

1992

ACS Symposium Series

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A model based on experiment and ab initio theory for the high-yield carbon--arc synthesis of C 60 and other fullerenes is presented. Evidence that is given indicates that the synthesis must start with the smallest units of carbon (atoms, dimers, etc.). The model is then broken into four steps: (1) the growth of carbon chains up to length C 10 from initial reactants present in the carbon vapor, (2) growth from chains into monocyclic rings (C 10 -C 20 ), (3) production and growth of three-dimensional reactive carbon networks (C 21 -C x , x = 30-40), and (4) growth of small fullerene cages via a closed--shell mechanism that exclusively produces C 60 , C 70 , and the higher fullerenes as the stable products.The carbon-arc synthesis of from solid graphite surely represents one of the most phenomenal phase transitions ever discovered. This synthetic technique, developed by Kratschmer, Fostiropoulos, and Huffman (7), has made bulk quantities of and other fullerenes available to the scientific community. This availability has stimulated a tremendous effort directed at characterizing this novel and exciting new class of molecules. One of the most fascinating aspects of the fullerenes, however, is the chemistry of their formation within the carbon arc. The synthesis is amazingly simple, and yet it produces results that are so fantastic and unexpected! The best experimental evidence (more on this later) indicates that the graphite reactant is vaporized in the carbon arc into the smallest units of carbon-atoms and possibly dimers-which then, through a concerted series of reactions, and in a limited range of pressures and temperatures, recombine to produce the spheroidal shells of carbon known as the fullerenes (2).How can this reaction scheme be understood? What are the individual chemical mechanisms that lead to the formation of the fullerenes? What reactive intermediates are produced in the carbon arc? How does the hightemperature chemical environment of the carbon arc produce the low-entropy

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Section: ) Which Quickly Proceed Through Step 4 To Produce the Fulmentioning

confidence: 72%

Synthesis of C₆₀ from Small Carbon Clusters

Heath

1992

ACS Symposium Series

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“…Recent experiments [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] as well as high level ab initio calculations [19][20][21][22][23][24][25][26][27][28][29][30] have largely vindicated the description originally put forth by Pitzer and Clementi [31] in 1959. Clusters with odd numbers of carbons possess linear singlet ground states, whereas even numbered clusters have two low-lying isomers, a triplet linear form and a singlet cyclic form.…”

Section: Introductionmentioning

confidence: 89%

Infrared laser spectroscopy of jet-cooled carbon clusters

et al. 1993

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We report the first structural characterization of the triplet isomer of C6. Forty-one rovibrational/fine structure transitions in the nu 4(sigma u) antisymmetric stretch fundamental of the C6 cluster have been measured by diode laser absorption spectroscopy of a supersonic carbon cluster beam. The observed spectrum is characteristic of a centrosymmetric linear triplet state with cumulene-type bonding. The measured ground state rotational constant B0 = 0.048 479 (10)cm-1 and the effective bond length r(eff) = 1.2868 (1) angstroms are in good agreement with ab initio predictions for the linear triplet (3 sigma g-) state of C6.

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“…These assignments are made based on the agreement between the peak centers (1899, 2138, and 2015 cm −1 ) and the experimentally observed gas-phase frequencies of 2138.315, 1898.376, and 2014.278 cm −1 for the v 5 and v 4 modes of C 7 and the v 6 mode of C 9 , respectively. [24][25][26][27][28]31 Transitions involving odd quanta along this FC forbidden mode could be explained by invoking HT-coupling in the neutral, which would require an excited neutral state of Σ + u symmetry according to Eq. (3).…”

Section: B Franck-condon Forbidden Featuresmentioning

confidence: 99%

“…13,14 Following this trend, both neutral and anionic C 7 and C 9 are found to be linear cumulenes through experimental and theoretical studies. The neutral clusters have been characterized with ion mobility spectrometry, 15 matrix isolation spectroscopy, [16][17][18][19][20][21][22][23] infrared laser absorption spectroscopy, [24][25][26][27][28][29][30][31] resonant multiphoton ionization spectroscopy, 32 and electronic structure calculations. 12,[33][34][35] This body of work shows that both neutral species have closed-shell 1 Σ + g ground electronic states.…”

Section: Introductionmentioning

confidence: 99%

Slow photoelectron velocity-map imaging of cold C7− and C9−

Babin

DeVine

Weichman

et al. 2018

The Journal of Chemical Physics

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High-resolution anion photoelectron spectra of cryogenically cooled C 7 − and C 9 − clusters obtained using slow photoelectron velocity-map imaging are presented, providing insight into the vibronic structure of neutral C 7 and C 9. These spectra yield accurate measurements of vibrational frequencies for the neutral clusters as well as electron affinities of 3.3517(4) and 3.6766(14) eV for C 7 and C 9 , respectively. In the C 7 − spectrum, transitions involving the previously unreported v 1 and v 2 symmetric stretching modes, as well as the v 9 , v 10 , and v 11 asymmetric bending modes, are assigned. Spin-orbit splitting is observed for several transitions in this spectrum, giving an energy difference of 28(6) cm −1 between the 2 Π 1/2g and 2 Π 3/2g spin-orbit levels of the C 7 − anion. In the spectrum of C 9 − , transitions involving the previously unreported symmetric stretch v 1 and the asymmetric bend v 11 are observed. In both spectra, several features are assigned to Franck-Condon forbidden transitions involving the doubly degenerate v 10 and v 11 modes of C 7 and the v 13 and v 14 modes of C 9. The appearance of these transitions is attributed to Herzberg-Teller coupling between the electronic states of the neutral clusters. Additional FC-forbidden transitions to states previously observed in gasphase infrared experiments are observed and attributed to vibronic coupling between the electronic states of the anion, resulting in non-totally symmetric character in the anion's full vibrational ground state. Finally, consideration of the energy dependence of detachment cross sections and Dyson orbital analyses reveal that addition of more carbon atoms to the linear chain results in photodetachment from delocalized molecular orbitals with increasing nodal structure, leading to threshold photodetachment cross sections that differ considerably from simple symmetry considerations.

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The C ₇ Cluster: Structure and Infrared Frequencies

Cited by 70 publications

References 20 publications

Synthesis of C₆₀ from Small Carbon Clusters

Synthesis of C₆₀ from Small Carbon Clusters

Infrared laser spectroscopy of jet-cooled carbon clusters

Slow photoelectron velocity-map imaging of cold C7− and C9−

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The C 7 Cluster: Structure and Infrared Frequencies

Cited by 70 publications

References 20 publications

Synthesis of C60 from Small Carbon Clusters

Synthesis of C60 from Small Carbon Clusters

Infrared laser spectroscopy of jet-cooled carbon clusters

Slow photoelectron velocity-map imaging of cold C7− and C9−

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Product

Resources

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The C ₇ Cluster: Structure and Infrared Frequencies

Synthesis of C₆₀ from Small Carbon Clusters

Synthesis of C₆₀ from Small Carbon Clusters