Validation of experimental charge-density refinement strategies
نویسندگان
چکیده
منابع مشابه
Validation of experimental charge-density refinement strategies: when do we overfit?
A cross-validation method is supplied to judge between various strategies in multipole refinement procedures. Its application enables straightforward detection of whether the refinement of additional parameters leads to an improvement in the model or an overfitting of the given data. For all tested data sets it was possible to prove that the multipole parameters of atoms in comparable chemical ...
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Urea and its derivatives have been the subject of extensive experimental and theoretical studies, using many techniques, mainly because of interesting physical and chemical properties [1-4]. Here we report a preliminary results of charge density study of N-phenylurea using synchrotron diffraction data collected at beamline F1 at HASYLAB/DESY. Although known from literature [1], the structure wa...
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The charge density (CD) distribution of an atom is the difference per unit volume between the positive charge of its nucleus and the distribution of the negative charges carried by the electrons that are associated with it. The CDs of the atoms in macromolecules are responsible for their electrostatic potential (ESP) distributions, which can now be visualized using cryo-electron microscopy at h...
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Sugars are the most stereochemically intricate family of biomolecules and present substantial challenges to anyone trying to understand their nomenclature, reactions or branched structures. Current crystallographic programs provide an abstraction layer allowing inexpert structural biologists to build complete protein or nucleic acid model components automatically either from scratch or with lit...
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Structure factors based on periodic density-functional (DFT) calculations on 25 molecular crystals have been used to evaluate trends in refined values of the kappa and kappa' expansion-contraction parameters of the Hansen-Coppens multipole formalism. As found previously and expected physically, the spherical-valence-shell kappa parameters are closely related to the net atomic charges, negative ...
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ژورنال
عنوان ژورنال: Acta Crystallographica Section A Foundations and Advances
سال: 2017
ISSN: 2053-2733
DOI: 10.1107/s2053273317089070