Extended Koopmans’ theorem in the adiabatic connection formalism: Applied to doubly hybrid density functionals

2020 ◽  
Vol 153 (4) ◽  
pp. 044109
Author(s):  
Yonghao Gu ◽  
Xin Xu
Keyword(s):  
Density Functionals ◽  
Koopmans Theorem

scholarly journals Computational Nutraceutics: Chemical Reactivity Properties of the Flavonoid Naringin by Means of Conceptual DFT

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jorge Ignacio Martínez-Araya ◽  
Guillermo Salgado-Morán ◽  
Daniel Glossman-Mitnik
Keyword(s):  
Active Sites ◽  
Chemical Reactivity ◽  
Fukui Function ◽  
Conceptual Dft ◽  
Density Functionals ◽  
Structure And Properties ◽  
Dual Descriptor ◽  
Reactivity Descriptors ◽  
Koopmans Theorem ◽  
Chemical Reactivity Descriptors

The M06 family of density functionals has been assessed for the calculation of the molecular structure and properties of the Naringin molecule. The chemical reactivity descriptors have been calculated through Conceptual DFT. The active sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices and the dual descriptorf(2)(r). A comparison between the descriptors calculated through vertical energy values and those arising from the Koopmans' theorem approximation has been performed in order to check for the validity of the last procedure.

Spatially Resolved Photoelectron Spectroscopy: Recent Progress and Future Plans

1990 ◽  
Vol 48 (2) ◽  
pp. 388-389
Author(s):  
A. M. Bradshaw
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Reactivity ◽  
Target Material ◽  
Orbital Energy ◽  
Light Sources ◽  
Analytical Technique ◽  
Hartree Fock ◽  
Spatially Resolved ◽  
Koopmans Theorem ◽  
Surface Analytical Technique

X-ray photoelectron spectroscopy (XPS or ESCA) was not developed by Siegbahn and co-workers as a surface analytical technique, but rather as a general probe of electronic structure and chemical reactivity. The method is based on the phenomenon of photoionisation: The absorption of monochromatic radiation in the target material (free atoms, molecules, solids or liquids) causes electrons to be injected into the vacuum continuum. Pseudo-monochromatic laboratory light sources (e.g. AlKα) have mostly been used hitherto for this excitation; in recent years synchrotron radiation has become increasingly important. A kinetic energy analysis of the so-called photoelectrons gives rise to a spectrum which consists of a series of lines corresponding to each discrete core and valence level of the system. The measured binding energy, EB, given by EB = hv−EK, where EK is the kineticenergy relative to the vacuum level, may be equated with the orbital energy derived from a Hartree-Fock SCF calculation of the system under consideration (Koopmans theorem).

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
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