Crystal structure fingerprints Detecting real polymorphism

3 Crystal structure fingerprints Detecting real polymorphism 

The construction of an intermolecular energetic fingerprint of an organic crystal 

Collect cell dimensions, space group information and atomic coordinates from an X-ray diffraction experiment use point-group symmetry, if any, to reconstmct an integer number of entire molecules. 

Having chosen one reference molecule, use crystal symmetry to generate molecules in its coordination sphere, that is, the twelve molecules whose centres of mass are closest to the center of mass of the reference molecule. 

Associate with each coordinated molecule the distance between its centre of mass and that of the reference one, / , the label of the symmetry operator connecting the two molecules, 0 (T, I, S, G, translation, inversion centre, screw axis, glide plane, respeetively, or no operation for different molecules in the asymmetric unit) and the molecule-molecule interaction energy, Ei. For planar molecules, also the dihedral angle between the two average molecular planes can be relevant. 

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