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Title: Anharmonicity in single-wall carbon nanotubes as evidenced by means of extended energy loss fine structure spectroscopy analysis

Abstract

A comparative study of the structure of free-standing parallel bundles of single-wall carbon nanotubes (SWCNTs), multiwalled carbon nanotubes (MWCNTs), and highly oriented pyrolytic graphite (HOPG) was achieved by means of transmission electron microscopy and electron energy loss spectroscopy analyses. In particular, the carbon K (1s) extended fine structure of SWCNTs is found to be characterized by an apparent contraction of the nearest neighbors distance. This contraction is interpreted here to originate from an asymmetric pair distribution function, mostly due to the high out-of-plane vibrational motion of the C atoms, as for the case of chemisorbed atoms on clean surfaces. In contrast, the MWCNTs did not exhibit any signature of such an anharmonic effect because of their more rigid structure. This indicates that the SWCNTs pair potential is significantly broader and its effect is much weaker than that experienced by the same C-C pair embedded in a multiwall nanotube.

Authors:
; ; ; ;  [1];  [2];  [3]; ;  [4]
  1. Dipartimento di Fisica, Unita INFM, Universita di Roma 'Tor Vergata', Via della Ricerca Scientifica 1, 00133 Rome (Italy)
  2. Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanita, 00161 Rome (Italy)
  3. Dipartimento di Igiene del Lavoro, ISPSEL, 00040 Monte Porzio Catone (Italy)
  4. Institut National de la Recherche Scientifique, INRS-Energie, Materiaux et Telecommunications 1650, Boulevard Lionel-Boulet, Case Postale 1020, Varennes, Quebec J3X 1S2 (Canada)
Publication Date:
OSTI Identifier:
20976662
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevB.75.035420; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHEMISORPTION; COMPARATIVE EVALUATIONS; DISTRIBUTION FUNCTIONS; ENERGY LOSSES; ENERGY-LOSS SPECTROSCOPY; FINE STRUCTURE; GRAPHITE; LAYERS; NANOTUBES; SURFACES; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Castrucci, P., Tombolini, F., Scarselli, M., Bini, S., De Crescenzi, M., Diociaiuti, M., Casciardi, S., El Khakani, M. A., and Rosei, F. Anharmonicity in single-wall carbon nanotubes as evidenced by means of extended energy loss fine structure spectroscopy analysis. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.035420.
Castrucci, P., Tombolini, F., Scarselli, M., Bini, S., De Crescenzi, M., Diociaiuti, M., Casciardi, S., El Khakani, M. A., & Rosei, F. Anharmonicity in single-wall carbon nanotubes as evidenced by means of extended energy loss fine structure spectroscopy analysis. United States. doi:10.1103/PHYSREVB.75.035420.
Castrucci, P., Tombolini, F., Scarselli, M., Bini, S., De Crescenzi, M., Diociaiuti, M., Casciardi, S., El Khakani, M. A., and Rosei, F. Mon . "Anharmonicity in single-wall carbon nanotubes as evidenced by means of extended energy loss fine structure spectroscopy analysis". United States. doi:10.1103/PHYSREVB.75.035420.
@article{osti_20976662,
title = {Anharmonicity in single-wall carbon nanotubes as evidenced by means of extended energy loss fine structure spectroscopy analysis},
author = {Castrucci, P. and Tombolini, F. and Scarselli, M. and Bini, S. and De Crescenzi, M. and Diociaiuti, M. and Casciardi, S. and El Khakani, M. A. and Rosei, F.},
abstractNote = {A comparative study of the structure of free-standing parallel bundles of single-wall carbon nanotubes (SWCNTs), multiwalled carbon nanotubes (MWCNTs), and highly oriented pyrolytic graphite (HOPG) was achieved by means of transmission electron microscopy and electron energy loss spectroscopy analyses. In particular, the carbon K (1s) extended fine structure of SWCNTs is found to be characterized by an apparent contraction of the nearest neighbors distance. This contraction is interpreted here to originate from an asymmetric pair distribution function, mostly due to the high out-of-plane vibrational motion of the C atoms, as for the case of chemisorbed atoms on clean surfaces. In contrast, the MWCNTs did not exhibit any signature of such an anharmonic effect because of their more rigid structure. This indicates that the SWCNTs pair potential is significantly broader and its effect is much weaker than that experienced by the same C-C pair embedded in a multiwall nanotube.},
doi = {10.1103/PHYSREVB.75.035420},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 3,
volume = 75,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • In this article an electron energy loss spectroscopy investigation of CN{sub x} thin films is reported. The bonding, composition, and structure are discussed and a more thorough extended energy loss spectroscopy investigation is carried out to determine the interatomic distances. The extended energy loss fine structure analysis reveals a component with an unusually high frequency in the data corresponding to an interatomic distance of approximately 7.3 {Angstrom}. This is suggested to originate from backscattering from distant curved atomic layers. {copyright} {ital 1997 American Institute of Physics.}
  • The electronic structure of single wall carbon nanotubes (SWNTs) in intact, undissolved buckypaper has been studied using STM and STS at 23 K. STS allows to distinguish between metallic, narrow gap semiconducting, and wide gap semiconducting SWNTs. In a statistical analysis we find a distribution ratio of 34{+-}6%:15{+-}4%:51{+-}7%, respectively. These ratios indicate that metallic SWNTs are preferentially generated in the buckypaper production process.
  • The local atomic structure of amorphous titanium diboride thin films, prepared by electron-beam vaporization (EBV) of the crystalline compound onto liquid-nitrogen-cooled substrates, was studied using extended x-ray-absorption fine-structure (EXAFS) and extended energy-loss fine-structure (EXELFS) techniques. From a comparison of the extended fine-structure spectra of the amorphous films with corresponding spectra of crystalline titanium diboride, accurate information was derived on the nature of the local structure, or short-range order, and on the coordination numbers, interatomic distances, and nanostructural atomic disorder in amorphous TiB/sub 2/. A relaxation of the interatomic spacing and a reduction of coordination number for the nearest-neighbor atoms wasmore » inferred for the amorphous state. Local prismatic coordination with random 90/sup 0/ rotations about prismatic planes is proposed as a likely atomic structure consistent with the data for the amorphous form. Finally, EXAFS and EXELFS were employed to examine in detail the structural changes induced in amorphous TiB/sub 2/ by variations in the EBV deposition parameters, and to determine a set of optimized parameters for the EBV deposition of a TiB/sub 2/ stable amorphous phase.« less
  • Thin films of hydrogenated and unhydrogenated titanium carbide, known to be amorphous from x-ray and electron diffraction studies, nevertheless exhibit short-range order at the level of the first-nearest-neighbor shell when studied by extended x-ray-absorption fine structure and extended electron-energy-loss fine structure. This short-range order appears to consist of the same octahedrally coordinated units present in crystalline titanium carbide (NaCl structure), where a titanium atom is surrounded by an octahedron of six carbon atoms and vice versa. The persistence of this basic structural unit is attributed to the difference in atomic radii between C and Ti and to the strong naturemore » of the Ti-C bond. A slight relaxation in interatomic distance relative to the crystalline state, which increases upon hydrogenation, is also observed. The atomic positions in the first coordination shell in amorphous titanium carbide are slightly displaced relative to the crystalline form. Yet, upon hydrogenation, this displacement decreases in the first shell, made of carbon atoms and vacancies, surrounding a Ti atom by 40% for the 4.5 at. % H and 60% for the 6 at. % H relative to the unhydrogenated amorphous TiC/sub x/ films. By contrast, the structural disorder in the first shell of Ti atoms surrounding a C atom is practically unaffected by the addition of hydrogen. These results imply that the hydrogen atoms, instead of occupying tetrahedral vacancies, fill carbon vacancies in the amorphous phase as they do in crystalline TiC/sub x/, in agreement with our previous findings from static secondary-ion mass spectroscopy and x-ray photoelectron spectroscopy.« less
  • No abstract prepared.