COHERENT NANODIFFRACTION FROM PHASE OBJECTS - CARBON NANOTUBES

Electron diffraction patterns obtained with a coherent incident beam o f diameter 1 nm or less do not, in general, show a center of symmetry even for thin phase objects. Experimental observations of nanodiffract ion patterns obtained from the walls of carbon nanotubes show asymmetr ies in the intensities of the first-order reflections from the carbon- layer stacking periodicity which are in agreement with calculations fr om a simple theoretical model. It is suggested that the measurement of such asymmetries may provide evidence regarding the structures of nan otubes of non-circular cross-section and of the end regions of tubes.