Topological Analysis of Chemical Bonding in Cyclophosphazenes

2001 ◽  
Vol 105 (21) ◽  
pp. 5280-5291 ◽  
Author(s):  
Victor Luaña ◽  
A. Martin Pendás ◽  
Aurora Costales ◽  
Gabino A. Carriedo ◽  
Francisco J. García-Alonso
Keyword(s):  
Chemical Bonding ◽  
Topological Analysis

scholarly journals Topology of the Electron Density and of Its Laplacian from Periodic LCAO Calculations on f-Electron Materials: The Case of Cesium Uranyl Chloride

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4227
Author(s):  
Alessandro Cossard ◽  
Silvia Casassa ◽  
Carlo Gatti ◽  
Jacques K. Desmarais ◽  
Alessandro Erba
Keyword(s):  
Electron Density ◽  
Chemical Bonding ◽  
Topological Analysis ◽  
Theoretical Description ◽  
Basis Functions ◽  
Quantum Mechanical ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Orbitals ◽  
Uranyl Chloride

The chemistry of f-electrons in lanthanide and actinide materials is yet to be fully rationalized. Quantum-mechanical simulations can provide useful complementary insight to that obtained from experiments. The quantum theory of atoms in molecules and crystals (QTAIMAC), through thorough topological analysis of the electron density (often complemented by that of its Laplacian) constitutes a general and robust theoretical framework to analyze chemical bonding features from a computed wave function. Here, we present the extension of the Topond module (previously limited to work in terms of s-, p- and d-type basis functions only) of the Crystal program to f- and g-type basis functions within the linear combination of atomic orbitals (LCAO) approach. This allows for an effective QTAIMAC analysis of chemical bonding of lanthanide and actinide materials. The new implemented algorithms are applied to the analysis of the spatial distribution of the electron density and its Laplacian of the cesium uranyl chloride, Cs2UO2Cl4, crystal. Discrepancies between the present theoretical description of chemical bonding and that obtained from a previously reconstructed electron density by experimental X-ray diffraction are illustrated and discussed.

The quantitative analysis of electrostatic potential and study of chemical bonding by electron diffraction structure analysis

2003 ◽  
Vol 218 (4) ◽  
Author(s):  
A. S. Avilov
Keyword(s):  
Quantitative Analysis ◽  
Electron Diffraction ◽  
Structure Analysis ◽  
Electrostatic Potential ◽  
Chemical Bonding ◽  
Quantitative Data ◽  
Topological Analysis ◽  
Diffraction Structure ◽  
Academy Of Sciences ◽  
Electron Diffractometry

AbstractThe development of the electron diffractometry methods jointly the analytical methods of electrostatic potential (ESP) reconstruction and its topological analysis allowd one to proceed to the quality new level of electron diffraction structure analysis (EDSA): investigation inner crystalline electrostatic field, which knowledge permitts to study the relation of the atomic structure with physical properties of crystals. The review of the last achivements in this direction, obtained in the Institute of Crystallography of Russian Academy of Sciences, in which EDSA method was discovered, is done. The possibility of the EDSA method to solve precise problems of quantitative analysis of the electrostatic potential is shown on the examples of investigations of the ESP distributions and chemical bonding in crystals with NaCl-type structure and covalent crystal Ge. It is also shown that quantitative data on the potential distribution considerably enlarge conceptions on the nature of interatomic and inetrmolecular interactions in crystals.

Is there a future for topological analysis in experimental charge-density research?

2017 ◽  
Vol 73 (3) ◽  
pp. 325-329 ◽  
Author(s):  
Birger Dittrich
Keyword(s):  
Charge Density ◽  
Intermolecular Interaction ◽  
Intermolecular Interactions ◽  
Chemical Bonding ◽  
Topological Analysis ◽  
Theoretical Chemistry ◽  
Research Tool ◽  
Interaction Energies ◽  
Research Focus ◽  
Experimental Charge Density

Topological analysis using Bader and co-worker'sAtoms in Moleculestheory has seen many applications in theoretical chemistry and experimental charge-density research. A brief overview of successful early developments, establishing topological analysis as a research tool for characterizing intramolecular chemical bonding, is provided. A lack of vision in many `descriptive but not predictive' subsequent studies is discussed. Limitations of topology for providing accurate energetic estimates of intermolecular interaction energies are put into perspective. It is recommended that topological analyses of well understood bonding situations are phased out and are only reported for unusual bonding. Descriptive studies of intermolecular interactions should have a clear research focus.

Chemical bonding in pentaerythritol at very low temperature or at high pressure: an experimental and theoretical study

2006 ◽  
Vol 62 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Elizabeth A. Zhurova ◽  
Vladimir G. Tsirelson ◽  
Vladimir V. Zhurov ◽  
Adam I. Stash ◽  
A. Alan Pinkerton
Keyword(s):  
High Pressure ◽  
Energy Density ◽  
Low Temperature ◽  
Intermolecular Interaction ◽  
Electron Density ◽  
Chemical Bonding ◽  
Topological Analysis ◽  
Interaction Energies ◽  
Molecular Layers ◽  
Very Low Temperature

Chemical bonding in the pentaerythritol crystal based on the experimental electron density at 15 (1) K, and theoretical calculations at the experimental molecular geometries obtained at room and low (15 K) temperatures have been analyzed and compared in terms of the topological analysis. Topological electron-density features corresponding to the high-pressure (1.15 GPa) geometry are also reported. In addition to the bond critical points (CPs) within the molecular layers, CPs between the atoms of different molecular layers have been located and the bonding character of these relatively weak interactions discussed. Atomic charges and energies have been integrated over the atomic basins delimited by the zero-flux surfaces, and the intermolecular interaction energies have been calculated. The interaction between molecular layers in the crystal becomes stronger both at very low temperature and high pressure, as demonstrated by the more negative intermolecular interaction energies, higher electron density and energy density values at the CPs, and sharper electronic-energy density profiles.

Radiation-induced surface decomposition

1983 ◽  
Vol 41 ◽  
pp. 368-369
Author(s):  
M. L. Knotek
Keyword(s):  
Ionizing Radiation ◽  
Atomic Structure ◽  
Chemical Bonding ◽  
Neutral Species ◽  
Radiation Induced ◽  
Physical And Chemical ◽  
Surface Decomposition ◽  
The Relationship ◽  
Electron And Photon ◽  
Surface Bond

Modern surface analysis is based largely upon the use of ionizing radiation to probe the electronic and atomic structure of the surfaces physical and chemical makeup. In many of these studies the ionizing radiation used as the primary probe is found to induce changes in the structure and makeup of the surface, especially when electrons are employed. A number of techniques employ the phenomenon of radiation induced desorption as a means of probing the nature of the surface bond. These include Electron- and Photon-Stimulated Desorption (ESD and PSD) which measure desorbed ionic and neutral species as they leave the surface after the surface has been excited by some incident ionizing particle. There has recently been a great deal of activity in determining the relationship between the nature of chemical bonding and its susceptibility to radiation damage.

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