Structures and vibrational frequencies of the carbon molecules C2-C18 calculated by density functional theory

Hutter, Jürg; Luethi, Hans P.; Diederich, François

doi:10.1021/ja00081a041

Cited by 231 publications

(196 citation statements)

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“…For the 4-AGNR-C n structure, the shortest bond length in odd-numbered chains (1.28 Å ) is shorter than that in even-numbered chains (1.31 Å ). The longest C-C bond length occurs at the ends of a chain (e.g., bond a, 29 joining the chain to the AGNR), in agreement with the calculations by Jin et al 14 The longest C(chain)-C(AGNR) bond length is 1.50 Å for odd-numbered chain with n ¼ 5 and 7 and 1.54 Å for even-numbered chain with n ¼ 6. For both odd-numbered and even-numbered chains, the shortest bond length is established next to the longest bond length (e.g., bond b).…”

Section: Resultssupporting

confidence: 88%

Progressive structural and electronic properties of nano-structured carbon atomic chains

Usanmaz¹,

Srivastava²

2013

Journal of Applied Physics

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Section: Resultssupporting

confidence: 88%

Progressive structural and electronic properties of nano-structured carbon atomic chains

Usanmaz¹,

Srivastava²

2013

Journal of Applied Physics

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“…For instance, structures for carbon clusters obtained using elaborate conventional ab initio methods 36 were correctly reproduced by B3LYP 37 but not by BP86. 38 (In addition, similar conclusions appear to hold for proton-bound dimers. 39 ) Since there is some evidence 35 that the B3PW91 method is somewhat more suitable for the calculation of charge distributions than B3LYP, particularly in strongly polar systems, we consider this functional here since the systems under study contain strongly polar bonds.…”

Section: Methodsmentioning

confidence: 58%

Structures of Furanosides: Density Functional Calculations and High-Resolution X-ray and Neutron Diffraction Crystal Structures

et al. 1999

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Highly accurate and precise crystal structures of methyl R-D-arabinofuranoside, methyl -D-ribofuranoside, methyl R-D-lyxofuranoside, and methyl R-D-xylofuranoside have been determined at 100 K by X-ray crystallography. The structures of methyl R-D-arabinofuranoside and methyl -D-ribofuranoside have also been determined at 15 K by neutron diffraction. Equilibrium (r e ) geometries of the same compounds were computed by means of density functional methods using a variety of exchange-correlation functionals and a sequence of basis sets. The validity of the computed results was assessed by several criteria including agreement between computed and observed bond distances and bond angles, agreement between computed and observed ring conformations, and basis set convergence of the computed geometrical parameters. Particular reference was made to computed internal hydrogen bond parameters, which are especially sensitive to the quality of the theoretical treatment. Because of the intrinsic sensitivity of the conformation of the five-membered ring to bond lengths and bond angles, molecular mechanics and small basis set SCF treatments are wholly inadequate. Local density functional theory also fails because of a tendency to strongly underestimate internal hydrogen bond distances. When the B3LYP exchange-correlation functional is used, bond lengths and bond angles agree with the neutron diffraction values to within their experimental uncertainty and the ring conformation is qualitatively correct, as long as a basis set of at least double-plus polarization quality (such as cc-pVDZ) is used. Further expansion of the basis set leads to more accurate equilibrium bond lengths and bond angles but does not appreciably affect the ring conformation. For methyl R-D-arabinofuranoside, methyl -D-ribofuranoside, and methyl R-D-xylofuranoside, there is very good correspondence between the best computed and observed ring conformations, even though some intermolecular hydrogen bonds in the crystal give way to internal hydrogen bonds in the predicted gas-phase structures. On the other hand, in the case of methyl R-D-lyxofuranoside, an O2H‚‚‚O4 internal hydrogen bond between the ring oxygen O4 and the hydroxyl hydrogen of a ring carbon (O2H) in the computed structure leads to a very large change of ring conformation from the northeast corner of the pseudorotation pathway (P ) 28°, crystal) to the southeast corner (P ) 130°, computed).

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“…These would then grow into linear chain of carbons C n , etc, for n < 10 (Hutter et al 1994). When n > 10 the carbon clusters prefer ring structure (Hutter et al 1994) because beyond n > 10 the energy gain in killing the dangling bonds at the two ends overcompensates for the strain energy incurred by folding up the chain. At around n > 30 the ring structures give way to fullerene structures (von Helden et al 1993a, b) because replacing more π-bonds by σ -bonds overcompensates for the strain of folding the 2D net.…”

Section: The Spiral Model Of Fullerene Formationmentioning

confidence: 99%

QM(DFT) and MD studies on formation mechanisms of C₆₀fullerenes

et al. 2000

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Abstract. One of the most puzzling aspects of fullerenes is how such complicated symmetric molecules are formed from a gas of atomic carbons, namely, the atomistic or chemical mechanisms. Are the atoms added one by one or as molecules (C 2 , C 3 )? Is there a critical nucleus beyond which formation proceeds at gas kinetic rates? What determines the balance between forming buckyballs, buckytubes, graphite and soot? The answer to these questions is extremely important in manipulating the systems to achieve particular products. A difficulty in current experiments is that the products can only be detected on time scales of microseconds long after many of the important formation steps have been completed. Consequently, it is necessary to use simulations, quantum mechanics and molecular dynamics, to determine these initial states. Experiments serve to provide the boundary conditions that severely limit the possibilities. Using quantum mechanical methods (density functional theory (DFT)) we derived a force field (MSXX FF) to describe one-dimensional (rings) and two-dimensional (fullerene) carbon molecules. Combining DFT with the MSXX FF, we calculated the energetics for the ring fusion spiral zipper (RFSZ) mechanism for formation of C 60 fullerenes. Our results shows that the RFSZ mechanism is consistent with the quantum mechanics (with a slight modification for some of the intermediates).

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Structures and vibrational frequencies of the carbon molecules C2-C18 calculated by density functional theory

Cited by 231 publications

References 3 publications

Progressive structural and electronic properties of nano-structured carbon atomic chains

Progressive structural and electronic properties of nano-structured carbon atomic chains

Structures of Furanosides: Density Functional Calculations and High-Resolution X-ray and Neutron Diffraction Crystal Structures

QM(DFT) and MD studies on formation mechanisms of C₆₀fullerenes

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Structures and vibrational frequencies of the carbon molecules C2-C18 calculated by density functional theory

Cited by 231 publications

References 3 publications

Progressive structural and electronic properties of nano-structured carbon atomic chains

Progressive structural and electronic properties of nano-structured carbon atomic chains

Structures of Furanosides: Density Functional Calculations and High-Resolution X-ray and Neutron Diffraction Crystal Structures

QM(DFT) and MD studies on formation mechanisms of C60fullerenes

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QM(DFT) and MD studies on formation mechanisms of C₆₀fullerenes