Hamburg 2001 – scientific programme
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O: Oberflächenphysik
O 39: Nanostrukturen (II)
O 39.6: Talk
Friday, March 30, 2001, 12:30–12:45, M
High Pressure Raman Studies of Solubilized Nanotubes — •Ulrich Schlecht1, U.D. Venkateswaran2, E.A. Brandsen2, J. Chen3, R.C. Haddon3, and A.M. Rao4 — 1Max-Planck-Inst. for Solid State Res., 70569 Stuttgart — 2Dept. of Physics, Oakland Univ., Rochester, MI 48309 — 3Dept. of Chemistry, Univ. of California, Riverside, CA 92521 — 4Dept. of Physics, Clemson Univ., Clemson, SC 29634
Raman spectroscopy has been used extensively to characterize as-prepared, purified and solubilized single wall carbon nanotubes (SWNTs) [1-3]. Recently, we have experimentally shown that the position of the radial band in the Raman spectra is sensitive to the environment in which the SWNTs reside [4]. In this talk, the effect of high pressure on the radial and tangential bands on bundled SWNTs will be presented [5], as well as on isolated tubes or small bundles, obtained from the solubilization process [3].
For the radial band in solubilized SWNTs, we observe a frequency upshift of ∼8 cm−1/GPa. This experimental result is in contradiction to the theoretically predicted value of 1.3 cm−1/GPa [5]. Furthermore, analysis of our data using the theory described in Ref. [6] shows that the van der Waals influence on the radial band frequency in solubilized SWNTs is reduced by ∼25 %, when compared with the corresponding value in bundled material.
[1] A.M. Rao et al., Science 275, 187 (’97); [2] S. Bandow et al., PRL 80, 3779 (’98); [3] J. Chen et al., Science 282, 95 (’98); [4] A.M. Rao et al., (submitted); [5] U.D. Venkateswaran et al., PRB 59, 10928 (’99); [6] C. Thomsen et al., Phys. Stat. Sol. B 215, 435 (’99)