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DOI: Author version available: Download author version PDF. Download Citation: Chem. Single-crystal X-ray diffraction studies on structural transformations of porous coordination polymers J. Zhang, P. Liao, H. Zhou, R. Lin and X. Chen, Chem. Search articles by author Jie-Peng Zhang. Pei-Qin Liao. Hao-Long Zhou. Rui-Biao Lin. Every detail of the reciprocal space right depends on the total information contained in the direct space left. Relative phase between waves.
Formula 1. Their moduli are directly related to the diffracted intensities. V represents the volume of the unit cell.
Appearance of a zone of the electron density map of a protein crystal, before it is interpreted. Electron density function in a point of coordinates x, y, z in a centrosymmetric unit cell.
Platts, Kenneth D. An automatic collection routine can then be used to collect a preliminary set of frames for determination of the unit cell. B Protein structures are described in four levels, from primary to quaternary structure. Please reconnect. X-ray crystallography can reveal the precise three-dimensional positions of most atoms in a protein molecule because x-rays and covalent bonds have similar wavelength, and therefore currently provides the best visualization of protein structure. Journal of Applied Crystallography , 46 4 ,
Formula 2. Structure factor for each diffracted beam. This equation is the Fourier transform of the electron density Formula 1. Formula 3. Illustration on the phase problem. Comparison between an optical microscope and the "impossible" X-ray microscope. There are no optical lenses able to combine diffracted X-rays to produce a zoomed image of the crystal contents atoms and molecules.
Arthur L. Patterson Max Ferdinand Perutz Scheme of a Patterson function derived from a crystal containing three atoms in the unit cell. The calculated function will show maximum values at the end of these vectors, whose heights are proportional to the product of the atomic numbers of the involved atoms. Formula 5. Argand diagram showing the scattering contribution from an anomalous scatterer in a matrix of normal scatterers.
This effect implies that Friedel's law fails.
Image taken from " Crystallography ". Fp represents the contribution from the normal scatterers to the structure factor of indices hkl. I -h,-k,-l , or I h,k,l vs.
I h,-k,l. Therefore, it is essential to use a synchrotron radiation facility, where wavelengths can be tuned easily. Merritt, as well as the practical summary prepared by Georg M. Rotation function.
Obviously, the calculated amplitudes can be rejected, because they are calculated from a partial structure and the experimental ones represent the whole structure. Historically this process was known as "succesive Fourier syntheses", because the electron density is calculated in terms of a Fourier sum. Formula 7. Structural resolution If you do not see a menu on the left, please, use this link. Molecular structure of a pneumococcal surface enzyme. Molecular packing in the crystal of a simple organic compound, showing its crystallographic unit cell.
Geometric details showing several molecular interactions in a fragment of the molecular structure of a protein. Motifs molecules, etc.
Unit cells are stacked in three dimensions, following the rules of the lattice, building the crystal.