Nonresonant Raman Spectrum Of Boron Doped Single Walled Carbon Nanotubes

In the present work, We use a force constant model to study the vibrationnel modes of boron doped single walled carbon nanotubes. This model is used to calculate the nonresonant Raman spectra of these nanomaterials in the framework of bond-polarisation theory by using either direct diagonalisation of the dynamical matrix or the spectral moments method. The effect of substitution of carbon by boron atoms shows that the higher Raman frequency region is dominated by a broad bond whereas the lower one is characterized by a shift of radial bonds.In the present work, We use a force constant model to study the vibrationnel modes of boron doped single walled carbon nanotubes. This model is used to calculate the nonresonant Raman spectra of these nanomaterials in the framework of bond-polarisation theory by using either direct diagonalisation of the dynamical matrix or the spectral moments method. The effect of substitution of carbon by boron atoms shows that the higher Raman frequency region is dominated by a broad bond whereas the lower one is characterized by a shift of radial bonds

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

International audiencePolarized Raman spectra of single-walled BC3 nanotubes(SBCNTs) are calculated as a function of their diameter, chirality, length,and bundle size using a classical force field combined with the bondpolarizabilitymodel. For isolated infinite tubes, we give a mathematicalmodel to estimate their diameter from their Raman spectra. Thetangential modes are sensitive to the tube chirality. The length shorteningof the tube below ∼50 nm leads to the appearance of several additionalRaman lines in the regions of breathing modes and tangential modes. ForSBCNT bundles, the position of the radial breathing mode is significantlyupshifted with respect to its position in isolated SBCNTs, and a specificbundle breathing-like mode is observed below 300 cm−1

Size effects on the infrared responses of boron carbide nanotubes

International audienceThe spectral moment's method combined with a force constant model is used to calculate the polarized infrared spectra in single-walled BC3 nanotubes. We discuss the evolution of these spectra as a function of the diameter, chirality and length of nanotubes. Our work provides benchmark theoretical data for the assignment of experimental infrared spectra

Theoretical infrared phonon modes in doublewalled carbon nanotubes

International audienceIn this theoretical work, we study the polarized infrared spectra of double-walled carbon nanotubes (DCNTs) as a function of their diameters, chiralities and lengths. For infinite DCNTs, mathematical relations are derived to estimate the diameter of the inner and outer tubes from the knowledge of their experimental mid-infrared spectra. The infrared spectra of DCNTs with a finite length are also calculated using the spectral moments method. We observe additional infrared bands as a function of the relative lengths of the inner and outer tubes. Bands located below 900 cm-1 give reliable information about these lengths