Selective probe of the morphology and local vibrations at carbon nanoasperities
- Research Center for Exotic Nanocarbons (JST), Shinshu University, 4-17-1, Wakasato, Nagano-city 380-8553 (Japan)
- Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi, Nagasaki 852-8521 (Japan)
- Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824 (United States)
- Department of Chemistry, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan)
We introduce a way to selectively probe local vibration modes at nanostructured asperities such as tips of carbon nanohorns. Our observations benefit from signal amplification in surface-enhanced Raman scattering (SERS) at sites near a silver surface. We observe nanohorn tip vibration modes in the range 200-500 cm{sup -1}, which are obscured in regular Raman spectra. Ab initio density functional calculations assign modes in this frequency range to local vibrations at the nanohorn cap resembling the radial breathing mode of fullerenes. Careful interpretation of our SERS spectra indicates presence of caps with 5 or 6 pentagons, which are chemically the most active sites. Changes in the peak intensities and frequencies with time indicate that exposure to laser irradiation may cause structural rearrangements at the cap.
- OSTI ID:
- 22047170
- Journal Information:
- Journal of Chemical Physics, Vol. 136, Issue 6; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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