Electronic states of an isolated nano-object made of single graphene layer have been successfully explored by means of electron energy-loss spectroscopy with high sensitivity and high spatial resolution. In further systematic study of various carbon nanostructures, the curvature and/or the interlayer coupling between adjacent graphene layers have been proved to govern the electronic states of carbon nanostructures. Using density functional theory, experimentally observed variations of the carbon $K\mathrm{}\left(1s\right)\mathrm{}$ near-edge fine structure have been ascribed mostly to the increasing curvature of the graphene layers.

• Received 22 September 2000

DOI:https://doi.org/10.1103/PhysRevB.63.165408