Electron scattering of nanoclusters and amorphous materials
	High resolution TEM image of fullerene-like CNx and electron diffraction pattern with its intensity distribution. The diffraction pattern indicates that the atomic short range orer of CNx is similar to that of graphite. For details see: Czigany Zs, Hultman L. Interpretation of electron diffraction patterns from amorphous and fullerene-like carbon allotropes Ultramicroscopy 110 (2010) 815-819 Outstanding Paper Award of EMS 2010
A model is proposed to calculate the electron diffraction of nanocrystaline materials through electron scattering of nanoclusters. Nanocrystalline material is modeled as aggregate of crystalline clusters of different size, shape and orientation. Amorphous materials are interpreted as nanocrystals of ultrafine grain (cluster) size composed of 10-30 atoms. Calculations of electron scattering of fullerene, graphite, graphene and diamond nanoclusters is used to evaluate the short range order in amorphous and fullerene-like allotropes of carbon. Diffuse peaks in the distribution of scattered intensity appear for average cluster size of 10-15 atoms. Nanocrystalline character appears when the average cluster size exceeds 60. In graphitic and fullerene carbon allotropes the position of peaks at ~1.2A and ~2A depends on cage curvature. Significant dependence is calculated for cages of smaller diameter than C60. High curvature induces peak shift to lower values of 1.08A and 1.72A, respectively, for curvature of C20.  A comparison with experimental high-resolution transmission electron microscopy (HRTEM) images and corresponding selected area electron diffraction patterns (SAED) makes it possible to classify the different amorphous and fullerene-like carbon allotropes (including fullerene-like CNx, CPx and MWCNT) by their atomic scale short range order.