a program to compute non-spherical atomic scattering factors for organic crystals
Discamb2tsc is a program built upon the new version of DiSCaMB library  and computes non-spherical atomic scattering factors from multipolar model  parametrized using MATTS databank (databank of Multipolar Atom Types from Theory and Statistical clustering; successor of UBDB2018 databank ) and prints them to the .tsc file . The .tsc file from discamb2tsc facilitate TAAM refinement  with olex2.refine from Olex2-1.3 .
-  Chodkiewicz et. al., J. Appl. Cryst., 2018, 51, 193-199
-  Hansen & Coppens, Acta Cryst. A, 1978, 34, 909-921
-  Kumar et al., Acta Cryst. A, 2019, 75, 398-408
-  Midgley et al., arXiv:1911.08847 [physics.chem-ph]
-  Jha et., al., Acta Cryst. B, 2020, B76
-  Dolomanov et al., J. Appl. Cryst., 2009, 42, 339-341
Discamb2tsc is available free of charge for non-commercial use, provided its use is acknowledged. All users have to fill the form (link to form) and agree to the license terms (link to license) to obtain the link to download discamb2tsc.
Discamb2tsc is also available for commercial use under a separate agreement. Please contact us for details.
For more informations look into the README file.
Current version of discamb2tsc should be considered as an alpha version.
Non-spherical atomic scattering factors are computed only for light elements (C, H, N, O, F, S, P, Cl). For other elements, and for unrecognized atom types, spherical scattering factors are assigned within Independent Atom Model approach, either from multipolar model (elements up to Z=36). Spherical multipolar model means: Pval like for neutral atom, Plm = 0, kappa1 & kappa2 = 1.0, with exception of hydrogen atom for which kappa1=1.16 is assigned. For any missing/non assigned atom type please look into the discamb2tsc.log file. For more details see the example of missing atom type.
Discamb2tsc computes X-ray scattering factors, for electron scattering factors please contact us directly.
Currently only the olex2.refine from Olex2-1.3 version is able to read .tsc file and apply it in the refinement.
Disordered molecules and organometallic molecules are not properly recognized yet, the work is in progress.
If you have any problems with discamb2tsc, you find a bug or some atom type is missing please contact us via firstname.lastname@example.org.
If you use discamb2tsc in your work please cite:
- P. Kumar, B. Gruza, S. A. Bojarowski, P. M. Dominiak: Extension of the transferable aspherical pseudoatom data bank for the comparison of molecular electrostatic potentials in structure–activity studies. Acta Cryst. A (2019) 75, 398-408.
- M. L. Chodkiewicz, S. Migacz, W. Rudnicki, A. Makal, J. A. Kalinowski, N. W. Moriarty, R. W. Grosse-Kunstleve, P. V. Afonine, P. D. Adams, P. M. Dominiak: DiSCaMB: a software library for aspherical atom model X-ray scattering factor calculations with CPUs and GPUs. J. Appl. Cryst. (2018). 51, 193-199.
- R. J. Gildea, L. J. Bourhis, O. V. Dolomanov, R. W. Grosse-Kunstleve, H. Puschmann, P. D. Adams and J. A. K. Howard: iotbx.cif: a comprehensive CIF toolbox. J. Appl. Cryst. (2011). 44, 1259-1263.
DiSCaMB ver. 2018 is a C++ library for calculation of structure factors from the Hansen-Coppens multipolar model of crystal electron density featuring parallel implementation for multicore processors and graphic processing units.
Source code authors: Michal Chodkiewicz & Szymon Migacz
People involved in the project: Michał L. Chodkiewicz, Szymon Migacz, Witold Rudnicki, Anna Makala, Nigel W. Moriarty, Ralf W. Grosse-Kunstleve, Pavel Afonine, Jarosław Kalinowski, Paul D. Adams, Paulina M. Dominiak