Insights on spin polarization through the spin density source function

Gatti, Carlo; Orlando, Ahmed M.; Presti, Leonardo Lo

doi:10.1039/c4sc03988b

Cited by 21 publications

(55 citation statements)

References 30 publications

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“…The same difficulties were previously identified for the reconstruction of spin density(s) by spin density SF (SDSF) . These difficulties were shown to be generated by two factors: (1) a low s , which is close to change its sign from positive to negative; and (2) a low number of points of radial numerical integration within core, because their s has undergone fast variation with major difficulties in its fitting . In common, s and ρ as shown in eq.…”

Section: Resultsmentioning

confidence: 54%

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When does a hydrogen bond become avan der Waalsinteraction? a topological answer

Tantardini

2019

J Comput Chem

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The hydrogen bond (H-bond) is among the most important noncovalent interaction (NCI) for bioorganic compounds. However, no "energy border" has yet been identified to distinguish it from van der Waals (vdW) interaction. Thus, classifying NCIs and interpreting their physical and chemical importance remain open to great subjectivity. In this work, the "energy border" between vdW and H-bonding interactions was identified using a dimer of water, as well as for a series of classical and nonclassical H-bonding systems. Through means of the quantum theory of atoms in molecules and in particular the source function, it was possible to clearly identify the transition from H-bonding to vdW bonding via analysis of the electronic structure. This "energy border" was identified both on elongating the interatomic interaction and by varying the contact angle. Hence, this study also redefines the "critic angle" previously proposed by Galvão et al. (J. Phys. Chem. A 2013, 117, 12668). Consequently, such "energy border" through an analysis of atomic basins volume variation was possible to identify the end of longrange interactions.

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Section: Resultsmentioning

confidence: 54%

“…In common, s and ρ as shown in eq. are rebuilt from their respectively Laplacian, for which for values in the order of 10 −3 e/Bohr 5 or lesser, the sign is uncertain with an impact on the calculation, respectively, of SDSF and SF …”

Section: Resultsmentioning

confidence: 99%

When does a hydrogen bond become avan der Waalsinteraction? a topological answer

Tantardini

2019

J Comput Chem

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“…The Source Function, having the attractive feature of being applicable on a common and rigorous basis to electron densities derived either from experiment or theory, appears to have wider applications than those already explored for discussing the nature of a chemical bond in more or less conventional situations. Detection of electron-delocalization effects, as highlighted in this paper, is one such new direction, another being the recent extension of the Source Function machinery to retrieve the atomic sources of the electron spin density (Gatti et al, 2015(Gatti et al, , 2016. In both cases, the already feasible or potential (in the case of electron spin densities) applications to observations derived from X-ray or polarized neutron diffraction experiments look particularly appealing and promising.…”

Section: Discussionmentioning

confidence: 99%

Source Function applied to experimental densities reveals subtle electron-delocalization effects and appraises their transferability properties in crystals

Gatti

Saleh

Presti

2016

Acta Crystallogr Sect B

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The Source Function (SF), introduced in 1998 by Richard Bader and Carlo Gatti, is succinctly reviewed and a number of paradigmatic applications to in vacuo and crystal systems are illustrated to exemplify how the SF may be used to discuss chemical bonding in both conventional and highly challenging cases. The SF enables the electron density to be seen at a point determined by source contributions from the atoms or a group of atoms of a system, and it is therefore well linked to the chemist's awareness that any local property and chemical behaviour is to some degree influenced by all the remaining parts of a system. The key and captivating feature of the SF is that its evaluation requires only knowledge of the electron density (ED) of a system, thereby enabling a comparison of ab initio and X-ray diffraction derived electron density properties on a common and rigorous basis. The capability of the SF to detect electron-delocalization effects and to quantify their degree of transferability is systematically explored in this paper through the analysis and comparison of experimentally X-ray derived Source Function patterns in benzene, naphthalene and (±)-8'-benzhydrylideneamino-1,1'-binaphthyl-2-ol (BAB) molecular crystals. It is shown that the SF tool recovers the characteristic SF percentage patterns caused by π-electron conjugation in the first two paradigmatic aromatic molecules in almost perfect quantitative agreement with those obtained from ab initio periodic calculations. Moreover, the effect of chemical substitution on the degree of transferability of such patterns to the benzene- and naphthalene-like moieties of BAB is neatly shown and quantified by the observed systematic deviations, relative to benzene and naphthalene, of only those SF contributions from the substituted C atoms. Finally, the capability of the SF to reveal electron-delocalization effects is challenged by using a promolecule density, rather than the proper quantum mechanical density, to determine the changes in SF patterns along the cyclohexene, 1,3-cyclohexadiene and benzene molecule series. It is shown that, differently from the proper quantum density, the promolecular density is unable to reproduce the SF trends anticipated by the increase of electron delocalization along the series, therefore ruling out the geometrical effect as being the only cause for the observed SF patterns changes.

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“…An in‐house code (PLOTDEN2016) has been used to evaluate the SF reconstructed partial electron densities and to plot them. PLOTDEN2016 is an updated and unpublished version of the PLOTDEN2013 code (also unpublished, but with brief description in the Supplementary Information of one previous paper by one of us) . The Diamond code was employed to draw all the atomic SF percentages ball‐and‐stick pictures.…”

Section: Calculationsmentioning

confidence: 99%

“…The entire field of study of the electron density is, in more than one way, undergoing a fast evolution on the front of obtaining quantum mechanically correct/constrained experimental electron densities, density matrices, and wavefunctions that can then be compared with those obtained from theory in benchmarking using tools such as the SF analysis as a base for comparison. The recent extension of the SF tool to the analysis of the electron spin densities provide further precious insights in such comparison benchmarking …”

Section: Closing Remarksmentioning

confidence: 99%

An Electron Density Source‐Function Study of DNA Base Pairs in Their Neutral and Ionized Ground States^†

et al. 2018

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The source function (SF) decomposes the electron density at any point into contributions from all other points in the molecule, complex, or crystal. The SF "illuminates" those regions in a molecule that most contribute to the electron density at a point of reference. When this point of reference is the bond critical point (BCP), a commonly used surrogate of chemical bonding, then the SF analysis at an atomic resolution within the framework of Bader's Quantum Theory of Atoms in Molecules returns the contribution of each atom in the system to the electron density at that BCP. The SF is used to locate the important regions that control the hydrogen bonds in both Watson-Crick (WC) DNA dimers (adenine:thymine (AT) and guanine:cytosine (GC)) which are studied in their neutral and their singly ionized (radical cationic and anionic) ground states. The atomic contributions to the electron density at the BCPs of the hydrogen bonds in the two dimers are found to be delocalized to various extents. Surprisingly, gaining or loosing an electron has similar net effects on some hydrogen bonds concealing subtle compensations traced to atomic sources contributions. Coarser levels of resolutions (groups, rings, and/or monomers-in-dimers) reveal that distant groups and rings often have non-negligible effects especially on the weaker hydrogen bonds such as the third weak CH⋅⋅⋅O hydrogen bond in AT. Interestingly, neither the purine nor the pyrimidine in the neutral or ionized forms dominate any given hydrogen bond despite that the former has more atoms that can act as source or sink for the density at its BCP. © 2018 Wiley Periodicals, Inc.

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Insights on spin polarization through the spin density source function

Abstract: The source function for the spin density s(r) is introduced, allowing the H and O influence on s(r) to be disentangled.

Cited by 21 publications

References 30 publications

When does a hydrogen bond become avan der Waalsinteraction? a topological answer

When does a hydrogen bond become avan der Waalsinteraction? a topological answer

Source Function applied to experimental densities reveals subtle electron-delocalization effects and appraises their transferability properties in crystals

An Electron Density Source‐Function Study of DNA Base Pairs in Their Neutral and Ionized Ground States^†

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Insights on spin polarization through the spin density source function

Abstract: The source function for the spin density s(r) is introduced, allowing the H and O influence on s(r) to be disentangled.

Cited by 21 publications

References 30 publications

When does a hydrogen bond become avan der Waalsinteraction? a topological answer

When does a hydrogen bond become avan der Waalsinteraction? a topological answer

Source Function applied to experimental densities reveals subtle electron-delocalization effects and appraises their transferability properties in crystals

An Electron Density Source‐Function Study of DNA Base Pairs in Their Neutral and Ionized Ground States†

Contact Info

Product

Resources

About

An Electron Density Source‐Function Study of DNA Base Pairs in Their Neutral and Ionized Ground States^†