Ab initio Hartree–Fock study of the electronic charge density of the cubic boron nitride and its comparison with experiments

1996 ◽  
Vol 52 (4) ◽  
pp. 586-595 ◽  
Author(s):  
A. Lichanot ◽  
P. Azavant ◽  
U. Pietsch
Keyword(s):  
Charge Transfer ◽  
Boron Nitride ◽  
Charge Density ◽  
Ab Initio ◽  
Cubic Boron Nitride ◽  
Electronic Charge ◽  
Total Density ◽  
Electronic Charge Density ◽  
Acta Cryst ◽  
Hartree Fock

The electronic charge density of cubic boron nitride is calculated within the ab initio Hartree–Fock approximation using the program CRYSTAL. Based on Debye hypothesis, the thermal motion of atoms is considered by disturbing the atomic orbitals by mean-square displacements given from experiment. The calculated difference charge density obtained by subtraction of the total density and that of an independent atomic model (IAM) is characterized by a charge-density accumulation between next neighbours slightly shifted towards the nitrogen. The calculated X-ray structure amplitudes are compared with two different data sets [Josten (1985). Thesis. University of Bonn, Germany; Eichhorn, Kirfel, Grochowski & Serda (1991). Acta Cryst. B47, 843–848]. In both cases, very good agreement is found beyond the 420 reflection. The first six structure amplitudes are generally lower or larger compared with Josten's and Eichhorn et al.'s data, respectively. Whereas our charge density can be interpreted by a balanced ratio between covalent overlap and electronic charge transfer between neighbouring valence shells, the density plots calculated from experimental data express either the charge transfer (Josten, 1985) or the covalency (Eichorn et al., 1991).

Electronic Charge Density and Electrostatic Potential of Pterin, 7,8-Dihydropterin and 5,6,7,8-Tetrahydropterin - an Ab initio Quantum Chemical Study

Pteridines ◽  
1998 ◽  
Vol 9 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Gilbert Reibnegger ◽  
Renate Horejsi ◽  
Karl Oettl ◽  
Walter Mlekusch
Keyword(s):  
Charge Density ◽  
Ab Initio ◽  
Electrostatic Potential ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Molecular Characteristics ◽  
Electronic Charge ◽  
Electronic Charge Density ◽  
Hartree Fock

SummaryAb initio quantum chemical computations at the Hartree-Fock 6-31g** level of theory were performed on pterin, 7,8-dihydropterin and 5,6,7,8 -tetrahydropterin. The resulting electronic charge density functions and the electrostatic potential functions of the molecules are visualized by graphical software. The results demonstrate the profound changes in electronic properties among these structurally closely related compounds. Our contribution may serve as a basis for deeper insight into the molecular characteristics, also of other chemically or biologically important pterin derivatives of different oxidation state.

scholarly journals Experimental core electron density of cubic boron nitride

2014 ◽  
Vol 70 (a1) ◽  
pp. C283-C283
Author(s):  
Nanna Wahlberg ◽  
Niels Bindzus ◽  
Lasse Bjerg ◽  
Jacob Becker ◽  
Bo Iversen
Keyword(s):  
Boron Nitride ◽  
Charge Density ◽  
Electron Density ◽  
Cubic Boron Nitride ◽  
Experimental Result ◽  
Total Density ◽  
Strongly Correlated ◽  
Core Density ◽  
Core Electron ◽  
The Core

The resent progress in powder diffraction provides data of quality beyond multipolar modeling of the valence density. As was recently shown in a benchmark study of diamond by Bindzus et al.[1] The next step is to investigate more complicated chemical bonding motives, to determine the effect of bonding on the core density. Cubic boron nitride lends itself as a perfect candidate because of its many similarities with diamond: bonding pattern in the extended network structure, hardness, and the quality of the crystallites.[2] However, some degree ionic interaction is a part of the bonding in boron nitride, which is not present in diamond. By investigating the core density in boron nitride we may obtain a deeper understanding of the effect of bonding on the total density. We report here a thorough investigation of the charge density of cubic boron nitride with a detailed modelling of the inner atom charge density. By combining high resolution powder X-ray diffraction data and an extended multipolar model an experimental modeling of the core density is possible.[3] The thermal motion is a problem since it is strongly correlated to the changes of the core density, but by combining the average displacement from a Wilson plot and a constrained refinement, a reasonable result has been obtained. The displacement parameters reported here are significantly lower than those previously reported, stressing the importance of an adequate description of the core density. The charge transfer from boron to nitrogen clearly affects the inner electron density, which is evident from theoretical as well as experimental result. The redistribution of electron density will, if not accounted for, result in increased thermal parameters. It is estimated that 1.7-2 electrons is transferred from boron to nitrogen.

Anion–π recognition between [M(CN)6]3− complexes and HAT(CN)6: structural matching and electronic charge density modification

2017 ◽  
Vol 46 (11) ◽  
pp. 3482-3491 ◽  
Author(s):  
Jedrzej Kobylarczyk ◽  
Dawid Pinkowicz ◽  
Monika Srebro-Hooper ◽  
James Hooper ◽  
Robert Podgajny
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Charge Density ◽  
Building Blocks ◽  
Electronic Charge ◽  
Anionic Complex ◽  
Anion Receptor ◽  
Electronic Charge Density ◽  
Ct System ◽  
Structural Matching

The first example of an anion–π charge transfer (CT) system between an anionic complex and a multisite anion receptor in the solid state and in solution was constructed based on prediction of structural and electronic matching of the building blocks.

Dynamical and Quantumchemical Characteristics of Electronic Charge Density Transfer Processes

2000 ◽  
Vol 214 (2) ◽  
Author(s):  
Wolfram Lorenz
Keyword(s):  
Charge Transfer ◽  
Charge Density ◽  
Condensed Matter ◽  
Chemical Processes ◽  
Electronic Charge ◽  
Partial Charge Transfer ◽  
Electronic Charge Density ◽  
Transfer Processes ◽  
Electronic Charge Transfer ◽  
Density Transfer

Exploration of electronic charge transfer requires quantumtheoretical support. On the line of previous work, the dynamical and quantumchemical foundation of electronic charge density transfer, or partial charge transfer in condensed-matter chemical processes, is explicated in terms of charge density conservation and local completeness of finite LCAO expansion. Accompanying discussion is focussed on recent

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