Chemical bonding in view of electron charge density and kinetic energy density descriptors

2009 ◽  
Vol 30 (7) ◽  
pp. 1093-1102 ◽  
Author(s):  
Heiko Jacobsen
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Charge Density ◽  
Chemical Bonding ◽  
Kinetic Energy Density ◽  
Electron Charge ◽  
Electron Charge Density

Localized-orbital locator (LOL) profiles of chemical bonding

2008 ◽  
Vol 86 (7) ◽  
pp. 695-702 ◽  
Author(s):  
Heiko Jacobsen
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Transition Metal Complexes ◽  
Chemical Bonding ◽  
Electron Pair ◽  
Kinetic Energy Density ◽  
Triple Bonds ◽  
Core Electrons ◽  
Localized Orbital ◽  
Hypervalent Molecules

We examine a recently introduced descriptor of chemical bonding, the localized-orbital locator (LOL), which is based on the kinetic-energy density (τ). Examples are presented for prototypical chemical bonds, such as single, double, and triple bonds, for bonding in transition metal complexes, for three-center two-electron bonds, as well as for hypervalent molecules. The topology of LOL is analyzed in terms of (3,–3) attractors (Γ). The influence of core electrons for chemical bonding is investigated, and a LOL-VSEPR (valence shell electron pair repulstion) relationship is established. Further, we compare LOL to the related electron localization function (ELF).Key words: chemical bonding, kinetic-energy density, localized-electron locator, VSEPR theory.

scholarly journals Pulsations of blue supergiants before and after helium core ignition

2013 ◽  
Vol 9 (S301) ◽  
pp. 321-324
Author(s):  
Jakub Ostrowski ◽  
Jadwiga Daszyńska-Daszkiewicz
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Kinetic Energy Density ◽  
Low Degree ◽  
Before And After

AbstractWe present results of pulsation analyses of B-type supergiant models with masses of 14 – 18 M⊙, considering evolutionary stages before and after helium core ignition. Using a non-adiabatic pulsation code, we compute instability domains for low-degree modes. For selected models in these two evolutionary phases, we compare properties of pulsation modes. Significant differences are found in oscillation spectra and the kinetic energy density of pulsation modes.

Environment Sensitive Embedding Energies of Impurities, and Grain Boundary Relaxation in Iron

1991 ◽  
Vol 238 ◽  
Author(s):  
Genrich L. Krasko
Keyword(s):  
Charge Density ◽  
First Principles ◽  
Electron Charge ◽  
Deformation Wave ◽  
Electron Charge Density ◽  
Impurity Site ◽  
Embedded Atom ◽  
Bcc Iron ◽  
Boundary Relaxation ◽  
Low Solubility

ABSTRACTImpurities, such as H, P, S, B, etc, have a very low solubility in iron, and therefore prefer to segregate at the grain boundaries (GBs). In order to analyze the energetics of the impurities on the iron GB, the LMTO calculations were performed on a simple 8-atom supercel 1 emulating a typical (capped trigonal prism) GB environment. The so-called “environment-sensitive embedding energies” were calculated for H, B, C, N, O, Al, Si, P, and S, as a function of the electron charge density due to the host atoms at the impurity site. It was shown that, at the electron charge density typical of a GB, B and C have the lowest energy among the analyzed impurities, and thus would compete with them for the site on the GB, tending to push the other impurities off the GB. The above energies were then used in a modified Finnis-Sinclair embedded atom approach for calculating the equilibrium interplanar distances in the vicinity of a (111) σ3 tilt GB plane, both for the clean GB and that with an impurity. These distances were found to be oscillating, returning to the equilibrium spacing between (111) planes in bulk BCC iron by the 10th-12th plane off the GB plane. H, B, C, N and O actually dampen the deformation wave (making the oscillation amplitudes less than in the clean GB), while, Al, Si, P and S result in an increase of the oscillations. The effect of B, C, N and O may be interpreted as cohesion enhancement; this conclusion supports our earlier first-principles results [1] on B and C.

scholarly journals Anisotropy of the field-induced kinetic energy density in Bi2212

2014 ◽  
Vol 433 ◽  
pp. 79-83 ◽  
Author(s):  
J.P. Peña ◽  
R.R. da Silva ◽  
P. Pureur
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Kinetic Energy Density

scholarly journals libKEDF: An accelerated library of kinetic energy density functionals

2017 ◽  
Vol 38 (17) ◽  
pp. 1552-1559 ◽  
Author(s):  
Johannes M. Dieterich ◽  
William C. Witt ◽  
Emily A. Carter
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Kinetic Energy Density ◽  
Density Functionals
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