The program CELSLC is used to calculate object transmission functions aka. phase gratings from atomic structure models. Files describing the atomic structure and other parameters are specified as arguments upon calling. The output is organized in so-called slice files, which are input for multislice calculations with the program MSA or the Dr. Probe GUI.
In order to calculate the elastic forward scattering of the incident electron by the electrostatic potential of the atomic structure, the crystal potential is projected to planes from very thin volume slices in the multislice approach. The elastic scattering potentials are calculated using the parameterization of Weickenmeier and Kohl [Acta Cryst. A47 (1991) p. 590-597] or alternatively those of Waasmaier and Kirfel [Acta Cryst. A51 (1995) p. 416-431]. CELSLC allows you also to use alternative or individual atomic form factors. Please contact the developer for more detailed explanations if you are interested.
Projected potentials of each structure slice are transformed to phase gratings describing the phase shift of the probing electron wave function caused by the screened Coulomb potentials of the atomic core charges. The program supports the calculation of phase gratings with different atomic configurations to model effects of thermal vibrations or to apply Debye-Waller factors and absorptive potentials to account for the effect of phonon excitations on elastic electron scattering.
Two different options are provided to apply absorptive potentials:
Example: Multiple atomic configurations of periodic periodic SrTiO3  for HAADF-STEM image simulations
50 structure variants are calculated for each of 2 structure slices on a 480 x 480
grid for 300 keV. The input structure model
consists of 3 x 3 unit cells. The output phase gratings will be stored in the files
celslc -cel STO_001_3x3.cel -slc STO001-300kV -nx 480 -ny 480 -nz 2 -nv 50 -fl -ht 300
Example: Periodic SrTiO3  for high-resolution TEM image simulations
Phase gratings are calculated of 4 structure slices are calculated on a 108 x 80 grid
for 300 keV electrons with Debye-Waller factors and absorptive form factors.
The input structure model consists of
2 SrTiO3 unit cells in  orientation. The output phase gratings
will be stored in the files
celslc -cel STO_110_2UC.cel -slc STO110-300kV -nx 108 -ny 80 -nz 4 -dwf -abs -ht 300