Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Raman-modes of index-identified free-standing single-walled carbon
  nanotubes   Using electron diffraction on free-standing single-walled carbon nanotubes we
have determined the structural indices (n,m) of tubes in the diameter range
from 1.4 to 3nm. On the same free-standing tubes we have recorded Raman spectra
of the tangential modes and the radial breathing mode. For the smaller
diameters (1.4-1.7nm) these measurements confirm previously established radial
breathing mode frequency versus diameter relations, and would be consistent
with the theoretically predicted proportionality to the inverse diameter.
However, for extending the relation to larger diameters, either a yet
unexplained environmental constant has to be assumed, or the linear relation
has to be abandoned.

21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
1
The categories of this paper are: cs
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th