Topological analysis of procrystal electron densities as a tool for computational modeling of solid electrolytes: A case study of known and promising potassium conductors

EDMAis a computer program for topological analysis of discrete electron densities according to Bader's theory of atoms in molecules. It locates critical points of the electron density and calculates their principal curvatures. Furthermore, it partitions the electron density into atomic basins and integrates the volume and charge of these atomic basins.EDMAcan also assign the type of the chemical element to atomic basins based on their integrated charges. The latter feature can be used for interpretation ofab initioelectron densities obtained in the process of structure solution. A particular feature ofEDMAis that it can handle superspace electron densities of aperiodic crystals in arbitrary dimensions.EDMAfirst generates real-space sections at a selected set of phases of the modulation wave, and subsequently analyzes each section as an ordinary three-dimensional electron density. Applications ofEDMAto model electron densities have shown that the relative accuracy of the positions of the critical points, the electron densities at the critical points and the Laplacian is of the order of 10−4or better.

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Unconstrained and X-ray constrained extremely localized molecular orbitals: analysis of the reconstructed electron density

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314019652 ◽

2014 ◽

Vol 70 (6) ◽

pp. 532-551 ◽

Cited By ~ 30

Author(s):

Leonardo H. R. Dos Santos ◽

Alessandro Genoni ◽

Piero Macchi

Keyword(s):

Dipole Moments ◽

Topological Analysis ◽

Molecular Orbitals ◽

Basis Sets ◽

Electron Densities ◽

X Ray ◽

Localized Molecular Orbitals ◽

New Strategy ◽

Electron Distributions ◽

Detailed Assessment

The recently developed X-ray constrained extremely localized molecular orbital (XC-ELMO) technique is a potentially useful tool for the determination and analysis of experimental electron densities. Molecular orbitals strictly localized on atoms, bonds or functional groups allow one to combine the quantum-mechanical rigour of the wavefunction-based approaches with the easy chemical interpretability typical of the traditional multipole models. In this paper, using very high quality X-ray diffraction data for the glycylglycine crystal, a detailed assessment of the capabilities and limitations of this new method is given. In particular, the effects of constraining the ELMO wavefunctions to experimental X-ray structure-factor amplitudes and the ability of the method to reproduce benchmark electron distributions have been accurately investigated. Topological analysis of the XC-ELMO electron densities and of the zero-flux surface-integrated charges and dipole moments shows that the new strategy is already reliable, provided that sufficiently flexible basis sets are used. These analyses also raise new questions and call for further improvements of the method.

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Topological analysis of experimental electron densities

Journal of Applied Crystallography ◽

10.1107/s0021889898011923 ◽

1999 ◽

Vol 32 (2) ◽

pp. 210-217 ◽

Cited By ~ 23

Author(s):

Mohamed Souhassou ◽

Robert H. Blessing

Keyword(s):

Amino Acid ◽

Crystal Structures ◽

Electron Density ◽

Topological Analysis ◽

Three Dimensional ◽

Electron Densities ◽

Acid Crystal ◽

Density Distributions ◽

Amino Acid Crystal ◽

Experimental Electron Density

Practical computing algorithms are described for analysing the topology of experimental electron density distributions represented as either three-dimensional grid densities or multipolar pseudoatom superpositions. The algorithms are implemented in the programNEWPROP, results from which are illustrated with applications to twoN-acetyl,C-methylamide blocked amino acid crystal structures.

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