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Sample Preparation and Transfer Protocol for In-Vacuum Long-Wavelength Crystallography on Beamline I23 at Diamond Light Source
Published on: April 23, 2021
Invarioms for improved absolute structure determination of light-atom crystal structures
B Dittrich1, M Strumpel, M Schäfer
1Chemistry M313, School of Biomedical, Biomolecular and Molecular Sciences, University of Western Australia, Crawley 6009, Australia. birger@cyllene.uwa.edu.au
Abstract:
The determination of molecular absolute configuration from an X-ray analysis for structures that contain only light elements is challenging owing to the weak anomalous dispersion signal. The achievable precision of the Flack x parameter for such structures is therefore limited, especially when the independent-atom model is employed. Invariom modelling can improve this situation. Invarioms are theoretically predicted pseudoatoms within the Hansen & Coppens multipole formalism. They are transferable from one molecule to another and provide generalized aspherical atomic form factors. It is shown that, by application of the invariom approach, the precision and standard uncertainty of the Flack x parameter and therefore the reliability of deducing molecular chirality in an absolute structure determination can be improved.
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