Abstract
Toroidal carbon nanotubes (TCNTs), which have been evaluated for their potential applications in terahertz communication systems, provide a challenge of some magnitude from a purely scientific perspective. A design approach to TCNTs, as well as a classification scheme, is presented based on the definition of the six hollow sections that comprise the TCNT, slicing each of them to produce a (possibly creased) planar entity, and projecting that entity onto a graphene lattice. As a consequence of this folding approach, it is necessary to introduce five- and seven-membered rings as defect sites to allow the fusing together of the six segments into final symmetric TCNTs. This analysis permits the definition of a number of TCNT geometry families containing from 108 carbons up to much larger entities. Based on density functional theory (DFT) calculations, the energies of these structural candidates have been investigated and compared with [60]fullerene. The structures with the larger tube diameters are computed to be more stable than C60, whereas the smaller diameter ones are less stable, but may still be within synthetic reach. Computational studies reveal that, on account of the stiffness of the structures, the vibrational frequencies of characteristic low-frequency modes decrease more slowly with increasing ring diameter than do the lowest optical excitation energies. It was found that this particular trend is true for the "breathing mode" vibrations when the diameter of the tubes is small, but not for more flexible toroidal nanotubes with larger diameters.
| Original language | English |
|---|---|
| Pages (from-to) | 3868-3875 |
| Number of pages | 8 |
| Journal | Chemistry - A European Journal |
| Volume | 17 |
| Issue number | 14 |
| DOIs | |
| Publication status | Published - Mar 28 2011 |
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Keywords
- carbon
- density functional calculations
- nanotubes
- optical and vibrational properties
- toroid topology
ASJC Scopus subject areas
- Chemistry(all)
Cite this
Optical and vibrational properties of toroidal carbon nanotubes. / Beuerle, Florian; Herrmann, Carmen; Whalley, Adam C.; Valente, Cory; Gamburd, Alexander; Ratner, Mark A; Stoddart, J. Fraser.
In: Chemistry - A European Journal, Vol. 17, No. 14, 28.03.2011, p. 3868-3875.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Optical and vibrational properties of toroidal carbon nanotubes
AU - Beuerle, Florian
AU - Herrmann, Carmen
AU - Whalley, Adam C.
AU - Valente, Cory
AU - Gamburd, Alexander
AU - Ratner, Mark A
AU - Stoddart, J. Fraser
PY - 2011/3/28
Y1 - 2011/3/28
N2 - Toroidal carbon nanotubes (TCNTs), which have been evaluated for their potential applications in terahertz communication systems, provide a challenge of some magnitude from a purely scientific perspective. A design approach to TCNTs, as well as a classification scheme, is presented based on the definition of the six hollow sections that comprise the TCNT, slicing each of them to produce a (possibly creased) planar entity, and projecting that entity onto a graphene lattice. As a consequence of this folding approach, it is necessary to introduce five- and seven-membered rings as defect sites to allow the fusing together of the six segments into final symmetric TCNTs. This analysis permits the definition of a number of TCNT geometry families containing from 108 carbons up to much larger entities. Based on density functional theory (DFT) calculations, the energies of these structural candidates have been investigated and compared with [60]fullerene. The structures with the larger tube diameters are computed to be more stable than C60, whereas the smaller diameter ones are less stable, but may still be within synthetic reach. Computational studies reveal that, on account of the stiffness of the structures, the vibrational frequencies of characteristic low-frequency modes decrease more slowly with increasing ring diameter than do the lowest optical excitation energies. It was found that this particular trend is true for the "breathing mode" vibrations when the diameter of the tubes is small, but not for more flexible toroidal nanotubes with larger diameters.
AB - Toroidal carbon nanotubes (TCNTs), which have been evaluated for their potential applications in terahertz communication systems, provide a challenge of some magnitude from a purely scientific perspective. A design approach to TCNTs, as well as a classification scheme, is presented based on the definition of the six hollow sections that comprise the TCNT, slicing each of them to produce a (possibly creased) planar entity, and projecting that entity onto a graphene lattice. As a consequence of this folding approach, it is necessary to introduce five- and seven-membered rings as defect sites to allow the fusing together of the six segments into final symmetric TCNTs. This analysis permits the definition of a number of TCNT geometry families containing from 108 carbons up to much larger entities. Based on density functional theory (DFT) calculations, the energies of these structural candidates have been investigated and compared with [60]fullerene. The structures with the larger tube diameters are computed to be more stable than C60, whereas the smaller diameter ones are less stable, but may still be within synthetic reach. Computational studies reveal that, on account of the stiffness of the structures, the vibrational frequencies of characteristic low-frequency modes decrease more slowly with increasing ring diameter than do the lowest optical excitation energies. It was found that this particular trend is true for the "breathing mode" vibrations when the diameter of the tubes is small, but not for more flexible toroidal nanotubes with larger diameters.
KW - carbon
KW - density functional calculations
KW - nanotubes
KW - optical and vibrational properties
KW - toroid topology
UR - http://www.scopus.com/inward/record.url?scp=79952851072&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79952851072&partnerID=8YFLogxK
U2 - 10.1002/chem.201002758
DO - 10.1002/chem.201002758
M3 - Article
C2 - 21344517
AN - SCOPUS:79952851072
VL - 17
SP - 3868
EP - 3875
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 14
ER -