Abstract
Many chapters in this Volume attest to the fact that experimental charge densities and one-electron properties derived directly from the diffraction data provide important information, much of which is not otherwise available experimentally. Nevertheless, the accuracy currently achieved is insufficient for a large number of issues on which experimental information would be very valuable. There is, for example, undisputed evidence for intermolecular effects on the electron density, but the majority of such effects are just below our present limit of accuracy. The difference between molecules in different solid phases, the effects of substituents on the charge density, the changes in ligand density on complex formation, the detailed analysis of theoretical results, are all accuracy limited at the present state of the field, in which, away from the nuclear positions, standard deviations in the deformation density of about 0.05eÅ-3 are achieved with careful diffractometer techniques. This means that in order for differences to be significant they must not be smaller than say 0.1 - 0.2eÅ-3 . What can be done to reduce this limitation so that charge density analysis may become a more generally useful analytical technique?
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References
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Coppens, P. (1991). The Use of Synchrotron Radiation and its Promise in Charge Density Research. In: Jeffrey, G.A., Piniella, J.F. (eds) The Application of Charge Density Research to Chemistry and Drug Design. NATO ASI Series, vol 250. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-3700-7_9
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