Spin Density Topology
Despite its role in spin density functional theory and it being the basic observable for describing and understanding magnetic phenomena, few studies have appeared on the electron spin density subtleties thus far. A systematic full topological analysis of this function is lacking, seemingly in contr...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-08-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/25/15/3537 |
| _version_ | 1797560467572391936 |
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| author | Giovanna Bruno Giovanni Macetti Leonardo Lo Presti Carlo Gatti |
| author_facet | Giovanna Bruno Giovanni Macetti Leonardo Lo Presti Carlo Gatti |
| author_sort | Giovanna Bruno |
| collection | DOAJ |
| description | Despite its role in spin density functional theory and it being the basic observable for describing and understanding magnetic phenomena, few studies have appeared on the electron spin density subtleties thus far. A systematic full topological analysis of this function is lacking, seemingly in contrast to the blossoming in the last 20 years of many studies on the topological features of other scalar fields of chemical interest. We aim to fill this gap by unveiling the kind of information hidden in the spin density distribution that only its topology can disclose. The significance of the spin density critical points, the 18 different ways in which they can be realized and the peculiar topological constraints on their number and kind, arising from the presence of positive and negative spin density regions, is addressed. The notion of molecular spin graphs, spin maxima (minima) joining paths, spin basins and of their <i>valence</i> is introduced. We show that two kinds of structures are associated with a spin–polarized molecule: the usual one, defined through the electron density gradient, and the <i>magnetic</i> structure, defined through the spin density gradient and composed in general by at least two independent spin graphs, related to spin density maxima and minima. Several descriptors, such as the spin polarization index, are introduced to characterize the properties of spin density critical points and basins. The study on the general features of the spin density topology is followed by the specific example of the water molecule in the <sup>3</sup>B<sub>1</sub> triplet state, using spin density distributions of increasing accuracy. |
| first_indexed | 2024-03-10T18:00:58Z |
| format | Article |
| id | doaj.art-621a856ee920415e9797dbad57df75a3 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T18:00:58Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-621a856ee920415e9797dbad57df75a32023-11-20T08:52:05ZengMDPI AGMolecules1420-30492020-08-012515353710.3390/molecules25153537Spin Density TopologyGiovanna Bruno0Giovanni Macetti1Leonardo Lo Presti2Carlo Gatti3Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, 20133 Milano, ItalyLaboratoire de Physique et Chimie Théoriques (LPCT), Université de Lorraine & CNRS, 1 Boulevard Arago, F–57078 Metz, FranceDipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, 20133 Milano, ItalyCNR–SCITEC, Istituto di Scienze e Tecnologie Chimiche sezione di via Golgi, c/o Università degli Studi di Milano, via Golgi 19, 20133 Milano, ItalyDespite its role in spin density functional theory and it being the basic observable for describing and understanding magnetic phenomena, few studies have appeared on the electron spin density subtleties thus far. A systematic full topological analysis of this function is lacking, seemingly in contrast to the blossoming in the last 20 years of many studies on the topological features of other scalar fields of chemical interest. We aim to fill this gap by unveiling the kind of information hidden in the spin density distribution that only its topology can disclose. The significance of the spin density critical points, the 18 different ways in which they can be realized and the peculiar topological constraints on their number and kind, arising from the presence of positive and negative spin density regions, is addressed. The notion of molecular spin graphs, spin maxima (minima) joining paths, spin basins and of their <i>valence</i> is introduced. We show that two kinds of structures are associated with a spin–polarized molecule: the usual one, defined through the electron density gradient, and the <i>magnetic</i> structure, defined through the spin density gradient and composed in general by at least two independent spin graphs, related to spin density maxima and minima. Several descriptors, such as the spin polarization index, are introduced to characterize the properties of spin density critical points and basins. The study on the general features of the spin density topology is followed by the specific example of the water molecule in the <sup>3</sup>B<sub>1</sub> triplet state, using spin density distributions of increasing accuracy.https://www.mdpi.com/1420-3049/25/15/3537spin densitytopologyquantum chemical topologyspin density critical pointsspin maxima and minima joining pathsmolecular spin graph |
| spellingShingle | Giovanna Bruno Giovanni Macetti Leonardo Lo Presti Carlo Gatti Spin Density Topology Molecules spin density topology quantum chemical topology spin density critical points spin maxima and minima joining paths molecular spin graph |
| title | Spin Density Topology |
| title_full | Spin Density Topology |
| title_fullStr | Spin Density Topology |
| title_full_unstemmed | Spin Density Topology |
| title_short | Spin Density Topology |
| title_sort | spin density topology |
| topic | spin density topology quantum chemical topology spin density critical points spin maxima and minima joining paths molecular spin graph |
| url | https://www.mdpi.com/1420-3049/25/15/3537 |
| work_keys_str_mv | AT giovannabruno spindensitytopology AT giovannimacetti spindensitytopology AT leonardolopresti spindensitytopology AT carlogatti spindensitytopology |