Fortgeschrittene Methoden der Quantenkristallographie zur Ladungsdichteuntersuchung von organischen und metallorganischen Verbindungen

eng: The Python3 based code - ReCrystal - has been developed as a novel iterative quantum crystallographic refinement method. This refinement method, similar to other transferable form factor approaches such as the Invariom model, uses theoretical multipole parameters to describe the deformation density in an iterative procedure, similar to Hirshfeld atomic refinement, using solid state calculations performed with CRYSTAL17. To start ReCrystal, a CIF, a Gaussian basis set, a DFT functional and the number of CPUs must be defined. The Pack-Monkhorst and Gilat shrinkage factors, which define a lattice in the first Brillouin zone, must also be specified. After k-point sampling, CRYSTAL17 calculates structure factors directly from the static electron density. Multipole parameters are generated from these structure factors using the XD program and fixed for least-squares refinement. The multipole parameters obtained from ReCrystal can be used for further charge density studies. The advantage of this approach is that multipole parameters can be obtained from high resolution calculated diffraction data, no database is required, and errors due to the model and errors resulting from the experiment are clearly separated. The benefit of considering periodic boundary conditions in single crystal structure refinement has been demonstrated for crystals with hydrogen bonding motifs and one extended structure.