Towards sub-A atomic resolution electron diffraction imaging of metallic nanoclusters: a simulation study of experimental parameters and reconstruction algorithms.

A simulation study is carried out to elucidate the effects of dynamical scattering, electron beam convergence angle and detection noise on atomic resolution diffraction imaging of small particles and to develop effective reconstruction procedures. Au nanoclusters are used as model because of their strong scattering. The results show that the dynamical effects of electron diffraction place a limit on the size of Au nanoclusters that can be reconstructed from the diffraction intensities with sufficient accuracy. For smaller Au nanoclusters, the simulations show that diffraction patterns recorded under the experimental conditions can be reconstructed using a combination of phase retrieval algorithms. The use of a low-resolution image is shown to be effective for reconstructing diffraction patterns without the central beam. A new algorithm for estimating the object support is proposed.