Locating symmetry elements in Patterson superposition maps
Abstract
A reciprocal space technique for determining the location of symmetry elements in Patterson superposition maps has been developed. The overlap of the superposition map with a copy of the map generated by the placement of the symmetry element at an arbitrary position is calculated using the Fourier transform coefficients of the original map. When the overlap is maximized, the symmetry element has been placed in the correct position. An alternate expression, which minimizes the phase differences in the Fourier coefficients, is also described. Expressions are developed for constraining the positions of different symmetry elements to meet space group constraints. For superposition maps containing predominantly one image of the structure, the phases of the Fourier coefficients can be modified, using the locations of the symmetry elements, to provide approximate phases for the observed structure factors.
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- Books Received
Articles in the same Issue
- Profile analysis of the supersatellite reflections in Labradorite – A synchrotron X-ray diffraction study
- Crystal structure determination from powder diffraction data by the application of a genetic algorithm
- The 3-regular nets with four and six vertices per unit cell
- Lattice potentials as an instrument in crystal chemistry. I. Theory and calculation1
- Lattice potentials as an instrument in crystal chemistry. II. Applications to the crystal bulk1
- Lattice potentials as an instrument in crystal chemistry. III. Applications to crystal surfaces1
- Locating symmetry elements in Patterson superposition maps
- Crystal structure determination of the TiSe2-based misfit layer compound (LaSe)1.20(TiSe2)2
- Conformation of ergopeptam and ergopeptine alkaloids (ergocristam and ergocristine)
- A comparison of the structures of RE3+ with proline
- Réduction de (+)-3-[di(alkylsulfanyl)méthylène]bornan-2-ones. Formation de complexes zinciques chiraux. Structure cristalline et dichroïsme circulaire
- Books Received
