scholarly journals Quantum pressure focusing in solids: a reconstruction from experimental electron density

2019 ◽  
Vol 75 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Vladimir G. Tsirelson ◽  
Adam I. Stash ◽  
Ilya V. Tokatly
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Electron Shell ◽  
Correlation Effects ◽  
Functional Theory ◽  
Quantum Electron ◽  
The Density Functional Theory ◽  
Bonding Mechanisms ◽  
Experimental Electron Density

Here an approach is presented for reconstructing the distribution of electronic internal quantum pressure in the electronic continuum of solids from the experimental electron density. Using the formalism of the density functional theory, the spatial inner-crystal map of the quantum pressure is obtained. The results are visualized via the indicator of quantum pressure focusing (IQPF) which reveals the regions where the pressure is concentrated or depleted due to quantum effects. IQPF contains all quantum electron-shell structure-forming contributions resulting from kinetic, exchange and correlation effects, and presents a clear picture of the chemical bond features in crystals with different type of bonding mechanisms.

Variationally Determined Occupation "Numbers" in an Extended Thomas-Fermi Scheme

1984 ◽  
Vol 39 (10) ◽  
pp. 919-923
Author(s):  
A. M. K. Müller
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Step Function ◽  
Correlation Effects ◽  
Fermi Theory ◽  
Functional Theory ◽  
Thomas Fermi ◽  
Occupation Numbers ◽  
The Density Functional Theory ◽  
Future Work

Abstract Thomas-Fermi theory is generalized by the introduction of an occupation distribution function f(s). The ansatz f(s) = Ɵ (s1 - s) of the conventional TF theory is derived from a variational principle. The implications with respect to the density functional theory are discussed. Future work is intended to include interaction, leading to deviations from the step function, which will account for correlation effects.

Fitting electron density as a physically sound basis for the development of interatomic potentials of complex alloys

2018 ◽  
Vol 20 (27) ◽  
pp. 18647-18656 ◽  
Author(s):  
Jose M. Ortiz-Roldan ◽  
Gustavo Esteban-Manzanares ◽  
Sergio Lucarini ◽  
Sofía Calero ◽  
Javier Segurado ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
New Method ◽  
Interatomic Potentials ◽  
Functional Theory ◽  
Starting Point ◽  
The Density Functional Theory

A new method to obtain physically sound EAM parameters using the density functional theory electron density as the starting point.

scholarly journals Perfluorobicyclo[2.2.0]hex-1(4)-ene as unique partner for Diels–Alder reactions with benzene: a density functional theory study

2021 ◽  
Vol 140 (2) ◽  
Author(s):  
Agnieszka Kącka-Zych ◽  
Patricia Pérez
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Diels Alder ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
One Step ◽  
Step Mechanism ◽  
Single Bonds ◽  
Reactivity Order

AbstractThe mechanism of the Diels–Alder reactions between perfluorobicyclo[2.2.0]hex-1(4)-ene (1a) and bicyclo[2.2.0]hex-1(4)-ene (1b) with benzene (2a) and naphthalene (2b) has been studied within the density functional theory at the MPWB1K/6-311G(d,p) level. The bonding pattern in these reactions is analyzed in the topology of the electron localization function within the bonding evolution theory perspective. The bonding electron density changes along the reaction paths reveal that the C–C bond formation takes place through a synchronous and non-concerted one-step mechanism and proceeds with a moderate activation energy. The reactivity order with 1a is 2a–2b. The reactions begin by the rupture of the double bond in the strained 1a-b molecules, and then two pseudoradical centers at the 1a-b fragments are created. Finally, at the same time, two new single bonds are formed in the cycloaddition products. The TSs proceed with high global electron density transfer providing a polar character at these reactions.

What correlation effects are covered by density functional theory?

2000 ◽  
Vol 98 (20) ◽  
pp. 1639-1658 ◽  
Author(s):  
Yuan He, Jurgen Grafenstein, Elfi Kraka,
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Correlation Effects ◽  
Functional Theory

scholarly journals Influence of Copper(I) Halides on the Reactivity of Aliphatic Carbodiimides

2020 ◽  
Vol 3 (1) ◽  
pp. 20
Author(s):  
Valentina Ferraro ◽  
Marco Bortoluzzi
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
General Formula ◽  
Electron Density ◽  
Density Functional ◽  
Functional Theory ◽  
Fukui Functions ◽  
Bond Lengths ◽  
Linear Complexes ◽  
Nitrogen Bond

The influence of copper(I) halides CuX (X = Cl, Br, I) on the electronic structure of N,N′-diisopropylcarbodiimide (DICDI) and N,N′-dicyclohexylcarbodiimide (DCC) was investigated by means of computational DFT (density functional theory) methods. The coordination of the considered carbodiimides occurs by one of the nitrogen atoms, with the formation of linear complexes having a general formula of [CuX(carbodiimide)]. Besides varying the carbon–nitrogen bond lengths, the thermodynamically favourable interaction with Cu(I) reduces the electron density on the carbodiimides and alters the energies of the (NCN)-centred, unoccupied orbitals. A small dependence of these effects on the choice of the halide was observable. The computed Fukui functions suggested negligible interaction of Cu(I) with incoming nucleophiles, and the reactivity of carbodiimides was altered by coordination mainly because of the increased electrophilicity of the {NCN} fragments.

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

Understanding the molecular mechanism of the stereoselective conversion of N-trialkylsilyloxy nitronates into bicyclic isoxazoline derivatives

2021 ◽  
Author(s):  
Agnieszka Kącka-Zych ◽  
Radomir Jasinski
Keyword(s):  
Density Functional Theory ◽  
Molecular Mechanism ◽  
Electron Density ◽  
Density Functional ◽  
Dft Method ◽  
Functional Theory ◽  
Molecular Electron ◽  
Molecular Electron Density Theory

Conversion of N-trialkylsilyloxy nitronates into bicyclic isoxazoline derivatives has been explored using Density Functional Theory (DFT) method within the context of the Molecular Electron Density Theory (MEDT) at the B97XD(PCM)/6-311G(d,p)...

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