Detection of cyclic carbon clusters. I. Isotopic study of the ν4(e′) mode of cyclic C6 in solid Ar

Abstract

The cyclic C6 cluster has been identified for the first time in Fourier transform infrared spectra of the products from the laser evaporation of graphite rods trapped in Ar at ∼10 K. Measurements on spectra produced using both 12C- and 13C-enriched rods combined with the results of new density functional theory calculations performed in the present work as well as previous calculations by Martin and Taylor, have resulted in the assignment of the most intense infrared active mode, ν4(e′)=1694.9 cm−1 of the cyclic C6 isomer with D3h symmetry. This assignment is based on excellent agreement of the frequency, 13C isotopic shifts, and relative intensities with the theoretical predictions.

Double Aromaticity and Ring Currents in All‐Carbon Rings

“…Recently, Kaizu et al [9] and Wakabayashi et al [10] used single-photon (10.5 eV) ionisation of neutrals to obtain mass spectra of carbon clusters that exhibit the predominance of C 4m + 2 (m = 2, 3,4). The presence of cyclic C n (n = 6, 8, 10,12,14,18,22) clusters was confirmed in several experiments. [11][12][13][14][15][16][17][18][19] Many theoretical studies have been performed for small carbon clusters C n .…”

Ab initio calculations of a new type of tubular carbon molecule based on multi-layered cyclic C6 structures

“…Over the last 20 years there have been many ab initio DFT calculations of the properties of cyclic C 6 [9][10][11][12][13][14][15][16][17][18] carried out using various formalisms and with a variety of different atomic basis sets. The results of these calculations together with matrix spectra of C 6 molecules [19][20][21][22] show that there are two isomers of cyclic C 6 , one having D 3h and the other having D 6h symmetry. The ground state of C 6 is concluded to have D 3h symmetry while the D 6h configuration is associated with a transition state ∼ 0.41 eV above the ground (D 3h ) state.…”

“…The present calculations indicate that the energy of the cyclic D 6h state is ∼ 0.53 eV lower than that of the linear C 6 isomer and imply that cyclic C 6 is a very stable molecule, but one that will exhibit high chemical activity. Cyclic C 6 has been identified in matrix spectra [19][20][21][22] and the D 3h symmetry of the ground state has been 0375-9601/$ -see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.physleta.2010.01.020 confirmed from infrared and Raman spectra.…”

Orientation effect on the electronic transport properties of C6 cluster

“…Using ab initio calculations, Raghavachari et al [14] in 1986 investigated the structures and energies of different C 6 isomers and predicted to be D 3h symmetry structure at the ground state. Combining Fourier transform infrared spectra with theoretical computations, two groups Presilla-Marquez et al [15] and Wang et al [16] in 1997 reported that the cyclic C 6 was detected in an Ar matrix at 10 K simultaneously. The ground state structure of C 6 cluster was also studied by Zhou et al [17] in 2004 who obtained that the distorted hexagon structure of the carbon cluster is the lowest in energy by using time-dependent density-functional theory.…”