Just like any other instrument used in experimental measurement, transmission electron microscope does not produce an image without introducing certain artefacts bearing characteristics of the contrast transfer function of the microscope, even when it is well aligned electro-optically. The purpose of performing image simulations is to separate artefacts induced into the image contrast by the interaction between the measuring instrument and the measured object. The artefacts come mainly from two sources: (a) Interaction between the incident electron beam and the specimen; (b) The influences on the electron wave from the electron optical system. Both are taken into account when image simulations are performed.
The former is described the dynamical electron diffraction formulas and the latter is described by the contrast phase contrast function.
We use Cerius2 to carry out image simulations at UNC.