C. Thomsen

Raman spectroscopy of graphite

We present a review of the Raman spectra of graphite from an experimental and theoretical point of view. The disorder–induced Raman bands in this material have been a puzzling Raman problem for almost 30 years. Double–resonant Raman scattering explains their origin as well as the excitation–energy dependence, the overtone spectrum and the difference between Stokes and anti–Stokes scattering. We develop the symmetry–imposed selection rules for double–resonant Raman scattering in graphite and point out misassignments in previously published works. An excellent agreement is found between the graphite phonon dispersion from double–resonant Raman scattering and other experimental methods.

Radial breathing mode of single-walled carbon nanotubes : Optical transition energies and chiral-index assignment

We present a comprehensive study of the chiral-index assignment of carbon nanotubes in aqueous suspensions by resonant Raman scattering of the radial breathing mode. We determine the energies of the first optical transition in metallic tubes and of the second optical transition in semiconducting tubes for more than 50 chiral indices. The assignment is unique and does not depend on empirical parameters. The systematics of the so-called branches in the Kataura plot are discussed; many properties of the tubes are similar for members of the same branch. We show how the radial breathing modes observed in a single Raman spectrum can be easily assigned based on these systematics. In addition, empirical fits provide the energies and radial breathing modes for all metallic and semiconducting nanotubes with diameters between 0.6 and 1.5 nm. We discuss the relation between the frequency of the radial breathing mode and tube diameter. Finally, from the Raman intensities we obtain information on the electron-phonon coupling.

Phonon dispersion of graphite by inelastic x-ray scattering

We present the full in-plane phonon dispersion of graphite obtained from inelastic x-ray scattering, including the optical and acoustic branches, as well as the mid-frequency range between the

Raman Scattering in Carbon Nanotubes

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Exciton Resonances Quench the Photoluminescence of Zigzag Carbon Nanotubes

and

Phonon dispersion of carbon nanotubes

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Raman scattering on silicon nanowires : The thermal conductivity of the environment determines the optical phonon frequency

points in the Brillouin zone, where experimental data have been unavailable so far. The existence of a Kohn anomaly at the

On Remote and Virtual Experiments in eLearning in Statistical Mechanics and Thermodynamics

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Polarized Raman and infrared vibrational analysis of (VO)2P2O7 single crystals

point is further supported. We fit a fifth-nearest neighbour force-constants model to the experimental data, making improved force-constants calculations of the phonon dispersion in both graphite and carbon nanotubes available.

Phonon dispersion of graphite

The vibrational properties of single-walled carbon nanotubes reflect the electron and phonon confinement as well as the cylindrical geometry of the tubes. Raman scattering is one of the prime techniques for studying the fundamental properties of carbon tubes and nanotube characterization. The most important phonon for sample characterization is the radial-breathing mode, an in-phase radial movement of all carbon atoms. In combination with resonant excitation it can be used to determine the nanotube microscopic structure. Metallic and semiconducting tubes can be distinguished from the high-energy Raman spectra. The high-energy phonons are remarkable because of their strong electron–phonon coupling, which leads to phonon anomalies in metallic tubes. A common characteristic of the Raman spectra in nanotubes and graphite is the appearance of Raman peaks that correspond to phonons from inside the Brillouin zone, the defect-induced modes. In this Chapter we first introduce the vibrational, electronic, and optical properties of carbon tubes and explain important concepts such as the nanotubes’ family behavior. We then discuss the Raman-active phonons of carbon tubes. Besides the vibrational frequencies and symmetries Raman spectroscopy also allows optical (excitonic) transitions, electron–phonon coupling and phase transitions in single-walled carbon nanotubes to be studied.