1.Introduction:If digital image matching between an experimental HREM-image and the simulated image fails, one of the suggested reasons is the “inaccuracy of the atomic form factors“ describing the electron scattering in common simulation packages using the free and neutral atom approximation from Hartree-Fock calculations [1]. In detail, three contributions within the usual form factor calculations are mainly missing: (i) the redistribution of charge in ionic crystals, (ii) the accumulation of charge away from atom sites in covalent crystals, (iii) the inclusion of thermal diffuse scattering (TDS) as well as the correlated vibration of atoms beyond the Einstein-approximation within the Debye-Waller factor (DWF) theory. Each of the three effects have been checked separately:
2.Simulations of TDS by Coupling of Molecular Dynamics Time Series to HREM- Multislice Calculations:70 snap shots of a series of structures of NiAl (4.9 × 5.1 × l0nm) are stored from an equilibrated molecular dynamics simulation with vibration amplitudes corresponding to room temperature.