Validation of missed space-group symmetry in X-ray powder diffraction structures with dispersion-corrected density functional theory

Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials

5 years ago

Validation of missed space-group symmetry in X-ray powder diffraction structures with dispersion-corrected density functional theory

$Validation of missed space-group symmetry in X-ray powder diffraction structures with dispersion-corrected density functional theory$

Martin U. Schmidt, Jacco van de Streek, Daniela Hempler

More than 600 molecular crystal structures with correct, incorrect and uncertain space-group symmetry were energy-minimized with dispersion-corrected density functional theory (DFT-D, PBE-D3). For the purpose of determining the correct space-group symmetry the required tolerance on the atomic coordinates of all non-H atoms is established to be 0.2 Å. For 98.5% of 200 molecular crystal structures published with missed symmetry, the correct space group is identified; there are no false positives. Very small, very symmetrical molecules can end up in artificially high space groups upon energy minimization, although this is easily detected through visual inspection. If the space group of a crystal structure determined from powder diffraction data is ambiguous, energy minimization with DFT-D provides a fast and reliable method to select the correct space group.Two hundred crystal structures with missed symmetry were investigated by dispersion-corrected density functional theory. In 98.5% of the cases the correct space group is found.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1107/S2052520617005935