No abstract

We report atomic resolution Z-contrast scanning transmission electron microscopy images that reveal the incorporation of I atoms in the form of helical chains inside single-walled carbon nanotubes. Density functional calculations and topological considerations provide a consistent interpretation of the experimental data. Charge transfer between the nanotube walls and the I chains is associated with the intercalation.

We report the first ellipsometric measurement of the fundamental optical constants (n,k) of C60 films deposited on Si(100) and Au overcoated Si(100) substrates. We obtain a highest occupied molecular orbital-lowest unoccupied molecular orbit (HOMO-LUMO) gap value of 2.3 eV, slightly larger than the gap values obtained from the x-ray photoelectron spectroscopy and electron-energy-loss spectroscopy experiments. The structure observed in the UV is discussed in terms of single-electron excitations across the HOMO-LUMO gap.

I.ow-temperature Raman scattering results for stage 1, 2, and 3 graphite-alkali-metal intercalation compounds are reported for in-plane modes using the Brewster-angle back-scattering geometry. Detailed full -spectra are presented for stage 1, 2, and 3 compounds of graphite-Rb. at 77 K. Particular attention is given to the structure which occurs at & 560 cm ' in the stage-1 compounds C,K, CSRb, C,Cs. This structure is shown to have two. components of different symmetries and is related to the zone-edge M, phonon mode of pristine graphite.

No abstract