scholarly journals Fundamental gaps with approximate density functionals: The derivative discontinuity revealed from ensemble considerations

2014 ◽  
Vol 140 (18) ◽  
pp. 18A540 ◽  
Author(s):  
Eli Kraisler ◽  
Leeor Kronik
Keyword(s):  
Density Functionals ◽  
Derivative Discontinuity

Density functionals and chemical bond, diatomic molecules

1989 ◽  
Vol 86 ◽  
pp. 853-859 ◽  
Author(s):  
Federico Moscardó ◽  
José Pérez-Jordá ◽  
Emilio San-Fabián
Keyword(s):  
Chemical Bond ◽  
Diatomic Molecules ◽  
Density Functionals

scholarly journals A Comparative Study of Oxygen and Hydrogen Adsorption on Strained and Alloy-Supported Pt(111) Monolayers

2021 ◽  
Vol 7 (7) ◽  
pp. 101
Author(s):  
Ian Shuttleworth
Keyword(s):  
Comparative Study ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Binding Energies ◽  
High Symmetry ◽  
Density Functionals ◽  
Functional Theory ◽  
Ligand Effects ◽  
Ferromagnetic Alloys ◽  
Depth Study

A comparative study of the unreacted and reacted uniaxially strained Pt(111) and the layered (111)-Pt/Ni/Pt3Ni and (111)-Pt/Ni/PtNi3 surfaces has been performed using density functional theory (DFT). An in-depth study of the unreacted surfaces has been performed to evaluate the importance of geometric, magnetic and ligand effects in determining the reactivity of these different Pt surfaces. An analysis of the binding energies of oxygen and hydrogen over the high-symmetry binding positions of all surfaces has been performed. The study has shown that O and H tend to bind more strongly to the (111)-Pt/Ni/Pt3Ni surface and less strongly to the (111)-Pt/Ni/PtNi3 surface compared to binding on the equivalently strained Pt(111) surfaces. Changes in the surface magnetisation of the surfaces overlaying the ferromagnetic alloys during adsorption are discussed, as well as the behaviour of the d-band centre across all surfaces, to evaluate the potential mechanisms for these differences in binding. An accompanying comparison of the accessible density functionals has been included to estimate the error in the computational binding energies.

scholarly journals Evaluation of van der Waals density functionals for layered materials

2018 ◽  
Vol 2 (3) ◽  
Author(s):  
Sherif Abdulkader Tawfik ◽  
Tim Gould ◽  
Catherine Stampfl ◽  
Michael J. Ford
Keyword(s):  
Van Der Waals ◽  
Layered Materials ◽  
Density Functionals

scholarly journals Calculation and interpretation of classical turning surfaces in solids

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Aaron D. Kaplan ◽  
Stewart J. Clark ◽  
Kieron Burke ◽  
John P. Perdew
Keyword(s):  
Density Functional ◽  
Molecular Crystals ◽  
Chemical Properties ◽  
Density Functionals ◽  
Compression And Expansion ◽  
Forbidden Regions ◽  
Internuclear Distances ◽  
Wide Gap ◽  
Equilibrium Geometries ◽  
Classical Picture

AbstractClassical turning surfaces of Kohn–Sham potentials separate classically allowed regions (CARs) from classically forbidden regions (CFRs). They are useful for understanding many chemical properties of molecules but need not exist in solids, where the density never decays to zero. At equilibrium geometries, we find that CFRs are absent in perfect metals, rare in covalent semiconductors at equilibrium, but common in ionic and molecular crystals. In all materials, CFRs appear or grow as the internuclear distances are uniformly expanded. They can also appear at a monovacancy in a metal. Calculations with several approximate density functionals and codes confirm these behaviors. A classical picture of conduction suggests that CARs should be connected in metals, and disconnected in wide-gap insulators, and is confirmed in the limits of extreme compression and expansion. Surprisingly, many semiconductors have no CFR at equilibrium, a key finding for density functional construction. Nonetheless, a strong correlation with insulating behavior can still be inferred. Moreover, equilibrium bond lengths for all cases can be estimated from the bond type and the sum of the classical turning radii of the free atoms or ions.

Sign in / Sign up

Export Citation Format

Share Document