Raman-active modes in homogeneous and inhomogeneous bundles of single-walled carbon nanotubes

Abstract

In the present work, the non-resonant Raman-active modes are calculated for several diameters, chiralities and sizes for homogeneous and inhomogeneous bundles of single-walled carbon nanotubes (BWCNTs), using the spectral moment's method (SMM). Additional intense Raman-active modes are present in the breathing-like modes (BLM) spectra of these systems in comparison with a single fully symmetric A(1g) mode characteristic of isolated nanotubes (SWCNTs). The dependence of the wavenumber of these modes in terms of diameters, lengths and number of tubes was investigated. We found that, for a finite (in)homogeneous bundle, additional breathing-like modes appear as a specific signature.

Computation of the infrared active modes in single-walled boron nitride nanotube bundles

“…The obtained fitting constant values are consistent with previous RBLM calculations [36], with the value 207.6 cm −1 , for the zigzag tubes. In comparison with the carbon nanotubes, a similar A/D trend has been obtained [36,37], with fitting constant values greater than those of BBNNTs. These results could be used to predict low wavenumbers for large diameter tubes.…”

Resonance Raman signature of intertube excitons in compositionally-defined carbon nanotube bundles

“…Interestingly, a small peak at ≈425 cm −1 is also observed to appear and grow in intensity with bundle size. We tentatively assign this peak as evidence of a predicted bundle breathing-like mode (BBLM) 31 . Alternatively, it may be an E -symmetry mode associated with the RBM 32 , 33 .…”

Tube-Length Dependence on Theoretical Raman Spectra of Single-Walled BC3 Nanotubes and Bundle Size Effect

“…For instance, the RBM shifts from 133 cm –1 in individual (5,5) SBCNT to 137 cm –1 in the infinite bundle of (5,5) tubes, and the BBLM is located at 249 cm –1 . Like in the SCNT bundles, the RBLM and BBLM modes arise from radial breathing and doubly degenerate (E symmetry) modes in SBCNTs. The wavenumber and the vibration pattern of these modes are determined by the competitions between the intertube and intratube interactions.…”