As mentioned before, for small/medium-sized molecules, a preliminary diagonal least squares refinement is automatically performed at the end of the DSR process to recognize the correct solution. The least squares procedure is also suitable for the complete crystal structure refinement. Its specific features are:
The constrained atoms are regularized to an ideal model structure of known geometry (i.e. benzene ring) and this rigid body is refined as compact unit assuming three translational parameters and three angles which define its orientation. The method used to compute the coordinates of the model follows the approach described by Arnott & Wonacott (1966). In order to build the internal Cartesian coordinates, the program uses the ASCII file Sir2014.gru which contains models described by the Z-matrix formalism.
The following restraints are available: bond distances, bond angles, planarity.
Fourier, least squares, hydrogens and restraints tools are accessible through the Graphical User Interface (GUI).
Created with the Personal Edition of HelpNDoc: Write EPub books for the iPad