https://doi.org/10.1140/epjb/e2005-00378-9
Nanotube field and one-dimensional fluctuations of C60 molecules in carbon nanotubes
1
Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
2
Institute of Physical Chemistry of the Russian Academy of Sciences,
Leninskii prospekt 31, 117915, Moscow, Russia
Corresponding author: a bart.verberck@ua.ac.be
Received:
24
June
2005
Revised:
21
September
2005
Published online:
9
December
2005
C molecules encapsulated in carbon nanotubes interact by van der Waals forces with the tube walls. The nanotube field leads to orientational confinement of the C molecules which depends on the nanotube radius. In small tubes with radius Å a fivefold symmetry axis of the molecule coincides with the tube axis, the center of mass of the molecule being located on the tube axis. The interaction between C molecules encapsulated in the nanotube is then described by a O2-rotor model on a one-dimensional (1-d) liquid chain with coupling between orientational and displacive degrees of freedom but no long-range order. This coupling leads to a temperature-dependent chain contraction. The structure factor of the 1-d liquid is derived. In tubes with larger radius the molecular centers of mass are displaced off the tube axis. The distinction of two groups of peapods with on- and off-axis molecules suggests an explanation of the apparent splitting of Ag modes of C in nanotubes measured by resonant Raman scattering.
PACS: 61.46.+w – Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals / 61.48.+c – Fullerenes and fullerene-related materials / 81.05.Tp – Fullerenes and related materials
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005