where y is in units of cm-1 and d is the nanotube diameter in nm.

Using this expression one can obtain the diameter of the SWNTs under study just by observing the position of the RBM band. However, a slight correction should be made in this formula since intertube coupling must be considered when the nanotubes are present in a bundle. This correction was achieved by using a Lennard-Jones potential to account for van der Waals interactions among the nanotubes in a bundle [86, 94]. A significant upshift of the RBM was found for nanotubes in bundles with respect to isolated nanotubes. The calculated data were best fitted by the nonlinear phe-nomenologic relation between the RBM frequency and the nanotube diameter, y =

0 0

Post a comment