Isomers of C24. Density functional studies including gradient corrections

Raghavachari, Krishnan; Zhang, Bulin; Pople, John A.; Johnson, Benny G.; Gill, Peter M. W.

doi:10.1016/0009-2614(94)00192-8

Cited by 86 publications

(58 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…21 There have been increasing research interests in small to medium-sized ͑n =20-36͒ carbon clusters since the discovery of the C 60 . [7][8][9][10][11][12][13]17,[22][23][24][25][26][27][28][29][30][31] In our previous paper ͑Paper I 26 ͒, we studied relative stabilities of various isomers of carbon cluster C 20 using high-level ab initio methods. In that study, the bowl-shaped "fullerene fragment" corannulene was theoretically identified as the ground-state isomer of C 20 , which has a lower energy than the ͑only͒ classical fullerene isomer of C 20 .…”

Section: Introductionmentioning

confidence: 99%

“…37 Starting from C 24 , previous theoretical calculations suggest that the classical fullerene cage is most likely the ground-state structure. 17,[22][23][24][25] An intermediate carbon phase, "cubic graphite" which has a simple cubic lattice formed by C 24 fullerene molecules and copolymerized by the square faces, has been characterized. 38 For its survival, an as-made fullerene should have certain degree of chemical stability with which the activation energy barrier for further chemical bonding with other identical or different-sized carbon clusters must be high enough to prevent fullerene from closure breaking.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ab initio calculation of carbon clusters. II. Relative stabilities of fullerene and nonfullerene C24

Shao

Bulusu

et al. 2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

Chemical stabilities of six low-energy isomers of C 24 derived from global-minimum search are investigated. The six isomers include one classical fullerene ͑isomer 1͒ whose cage is composed of only five-and six-membered rings ͑5 / 6-MRs͒, three nonclassical fullerene structures whose cages contain at least one four-membered ring ͑4-MR͒, one plate, and one monocyclic ring. Chemical and electronic properties of the six C 24 isomers are calculated based on a density-functional theory method ͑hybrid PBE1PBE functional and cc-pVTZ basis set͒. The properties include the nucleus-independent chemical shifts ͑NICS͒, singlet-triplet splitting, electron affinity, ionization potential, and gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital ͑HOMO-LUMO͒ gap. The calculation suggests that the neutral isomer 2, a nonclassical fullerene with two 4-MRs, may be more chemically stable than the classical fullerene ͑isomer 1͒. Analyses of molecular orbital NICS show that the incorporations of 4-MRs into the cage considerably reduce paratropic contributions from HOMO, HOMO-1, and HOMO-2, which are mainly responsible for the sign change in NICS from positive for isomer 1 ͑42͒ to negative ͑−19͒ for isomer 2, although C 24 clusters satisfy neither 4N + 2 nor 2͑N +1͒ 2 aromaticity rule. Anion photoelectron spectra of four cage isomers, one plate, one monocyclic ring, and one tadpole isomer, as well as three bicyclic ring isomers are calculated. The simulated photoelectron spectra of monoand bicyclic rings ͑with C 1 symmetry͒ appear to match the measured HOMO-LUMO gap ͑between the first and second band in the experimental spectra͒ ͓S. Yang et al., Chem. Phys. Lett. 144, 431 ͑1988͔͒. Nevertheless, the nonclassical fullerene isomers 3 and 4 apparently also match the measured vertical detachment energy ͑2.90 eV͒ reasonably well. These results suggest possible coexistence of nonclassical fullerene isomers with the mono-and bicyclic ring isomers of C 24 − under the experimental conditions.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ab initio calculation of carbon clusters. II. Relative stabilities of fullerene and nonfullerene C24

Shao

Bulusu

et al. 2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…Rrthlisberger and Klein [90] report that underestimation of the barrier to rotation in n-butane is corrected when gradient corrections are incorporated. Raghavachari et al [91] have begun the much needed effort to explore the effectiveness of DFT methods in predicting equilibrium geometries, vibrational frequencies, atomization energies, and other fundamental chemical properties. Meanwhile, functional forms are being developed, some with a view to hybridizing HF and DFT theory.…”

Section: Methodsmentioning

confidence: 99%

Some recent applications of ab initio electronic structure methods to metal, semimetal, and molecular clusters

Binning

Ishikawa

1995

Struct Chem

View full text Add to dashboard Cite

Recent experimental and theoretical cluster studies are reviewed. Areas of current and developing interest in theoretical and computational chemistry are identified. Some promising methods applied to metal clusters, main group clusters, molecular clusters, spectroscopy, and models of cluster-molecule reactions are indicated. Results of calculations on small hydrogenated lithium clusters and hydrated sodium clusters are discussed in some detail.

show abstract

“…Raghavachari et al [9] consider some corannulene-like form (bowl) of carbon molecules. Thus, inspired by that models, we present a preliminary example on Figure 1 with 38 carbons, 20 faces, and 56 edges.…”

Section: Calculationsmentioning

confidence: 99%