Controlled orientation of ellipsoidal fullerene C70 in carbon nanotubes

Density functional theory calculations predict two orientations for ellipsoidal C70 fullerenes inside single-walled carbon nanotubes (SWNTs) of different sizes: transverse orientation for C70 in (11,11) nanotubes (d=14.9 Å) and longitudinal orientation for C70 in (10,10) nanotubes (d=13.6 Å). SWNTs with these diameters have been prepared and filled with the C70 fullerenes, and characterized by Raman spectroscopy and high-resolution transmission electron microscopy, showing the orientations predicted by theory.