Electronic shell structure of antimony cluster

1992 ◽  
Vol 70 (12) ◽  
pp. 1205-1208
Author(s):  
B. N. Onwuagba
Keyword(s):  
Binding Energy ◽  
Ground State ◽  
Density Functional ◽  
Magic Numbers ◽  
Local Spin Density Approximation ◽  
Correlation Effects ◽  
Jellium Model ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Relative Binding

The ground-state properties of antimony clusters are investigated in the framework of density functional theory. The exchange correlation effects were included in the local spin density approximation and a spherical jellium model is used to calculate the total energy, binding energy, relative binding-energy change, and ionization potential with a view to understanding the mechanism leading to the magic-numbers exhibited by this class of higher valence clusters.

scholarly journals Application of time-dependent current-density-functional theory to nonlocal exchange-correlation effects in polymers

2003 ◽  
Vol 118 (3) ◽  
pp. 1044-1053 ◽  
Author(s):  
M. van Faassen ◽  
P. L. de Boeij ◽  
R. van Leeuwen ◽  
J. A. Berger ◽  
J. G. Snijders
Keyword(s):  
Density Functional Theory ◽  
Current Density ◽  
Density Functional ◽  
Time Dependent ◽  
Correlation Effects ◽  
Functional Theory ◽  
Exchange Correlation

On the role of steric and exchange–correlation effects in halogenated complexes

2021 ◽  
Author(s):  
Mojtaba Alipour ◽  
Parisa Fallahzadeh
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Partitioning ◽  
Correlation Effects ◽  
Functional Theory ◽  
Exchange Correlation

Density functional theory formalisms of energy partitioning schemes are utilized to find out what energetic components govern interactions in halogenated complexes.

scholarly journals London dispersion forces without density distortion: a path to first principles inclusion in density functional theory

2020 ◽  
Vol 224 ◽  
pp. 145-165
Author(s):  
Derk Pieter Kooi ◽  
Paola Gori-Giorgi
Keyword(s):  
Ground State ◽  
First Principles ◽  
Density Functional ◽  
Dispersion Forces ◽  
Density Functionals ◽  
Functional Theory ◽  
Exchange Correlation ◽  
State Densities ◽  
London Dispersion ◽  
London Dispersion Forces

We analyse a path to construct density functionals for the dispersion interaction energy from an expression in terms of the ground state densities and exchange–correlation holes of the isolated fragments.

Ab initio Correlation Effects in Density Functional Theories: An Electron-Distribution-Based Study for Neon

2005 ◽  
Vol 70 (8) ◽  
pp. 1157-1176 ◽  
Author(s):  
Karol Jankowski ◽  
Ireneusz Grabowski ◽  
Krzysztof Nowakowski ◽  
Jan Wasilewski
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Physical Nature ◽  
Correlation Effects ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Hartree Fock ◽  
Brueckner Orbitals ◽  
Local Gradient ◽  
The Impact

We have briefly reviewed the idea of studies aiming at such a bridging of the methodological gap between ab initio methods (or wave function theory (WFT)) and density functional theory (DFT) that would afford carrying over results concerning details of the structure of correlation effects from one method to the other. Special attention is paid to the problem of coverage of the WFT correlation effects by the exchange-correlation functionals of DFT. A short survey of the concept of supplementing energy-based investigations in this field by electron-density-based studies is given and illustrated by results for the Ne atom. DFT densities are generated for representatives of all four generations of presently used exchange-correlation functionals, including the recently developed orbital-dependent one. These densities are compared with WFT densities calculated at the MP2, MP3, and Brueckner determinant levels. It is found that the exchange-only parts of the local, gradient-corrected, and hybrid functionals account for the bulk of WFT correlation effects. The impact of the associated correlation functionals is very small and their physical nature is not quite clear. The situation is different for the orbital-dependent functional for which the exchange-only functional provides an almost exact description of the Hartree-Fock density. Here, the correlation effects are entirely represented by the correlation functional. Attention is also paid to the suitability of Kohn-Sham orbitals for the description of WFT correlation effects and to their presumptive similarity with Brueckner orbitals.

Fast computation of DFT nuclear gradient with multiresolution*This article is dedicated to Dr. Russell J. Boyd for his distinguished career in chemical research.

2011 ◽  
Vol 89 (6) ◽  
pp. 657-662 ◽  
Author(s):  
Nicholas J. Russ ◽  
Chun-min Chang ◽  
Jing Kong
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Density Functional Theory Calculation ◽  
Computational Cost ◽  
Basis Sets ◽  
Local Spin Density Approximation ◽  
Functional Theory ◽  
Exchange Correlation ◽  
The Impact

We present an efficient algorithm for evaluating the exchange-correlation contribution to the nuclear gradients of density-functional theory calculation within the local spin-density approximation. The algorithm is an extension of the multiresolution exchange-correlation (mrXC) method, which treats smooth and compact parts of the electron density separately. The nuclear gradient of the smooth density is calculated on the even-spaced grid while the compact part of the density is handled on the normal atom-centered grid (ACG). The overall formulism is still formally based on the ACG, and thus does not change the results of the existing ACG-based algorithms for all-electron density-functional theory (DFT) calculations. The variation of the positions and weights of ACG owing to the nuclear perturbation is also handled rigorously. Benchmark calculations with different basis sets and sizes of ACG show that mrXC reduces the computational cost by several times without loss of accuracy. It also lessens the impact on the CPU time when the size of the ACG is increased.

scholarly journals Hydrogen storage on platinum decorated graphene: A first-principles study

BIBECHANA ◽  
2014 ◽  
Vol 11 ◽  
pp. 113-122 ◽  
Author(s):  
S Lamichhane ◽  
N Pantha ◽  
NP Adhikari
Keyword(s):  
Binding Energy ◽  
First Principles ◽  
Density Functional ◽  
Pristine Graphene ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
London Dispersion ◽  
Quantum Espresso ◽  
London Dispersion Forces

Adsorption of gaseous/molecular hydrogen on platinum (Pt) decorated and pristine graphene have been studied systematically by using density functional theory (DFT) level of calculations implemented by Quantum ESPRESSO codes. The Perdew-Burke-Ernzerhof (PBE) type generalized gradient approximation (GGA) exchange-correlation functional and London dispersion forces have been incorporated in the DFT-D2 level of algorithm for short and long range electron-electron interactions, respectively. With reference to the binding energy of Pt on different symmetry sites of graphene supercells, the bridge (B) site has been predicted as the best adsorption site. In case of 3×3 supercell of graphene (used for detail calculations), the binding energy has been estimated as 2.02 eV. The band structure and density of states calculations of Pt adatom graphene predict changes in electronic/magnetic properties caused by the atom (Pt). The adatom (Pt) also enhances the binding energy per hydrogen molecule in Pt-graphene comparing to that in pristine graphene and records the values within the range of 1.84 eV to 0.13 eV for one to eight molecules, respectively. DOI: http://dx.doi.org/10.3126/bibechana.v11i0.10389 BIBECHANA 11(1) (2014) 113-122

THERMAL PROPERTIES OF THE XB2(X = Ag, Au) COMPOUNDS: A FIRST-PRINCIPLES STUDY

2013 ◽  
Vol 27 (12) ◽  
pp. 1350046
Author(s):  
HAVVA BOGAZ OZISIK ◽  
KEMAL COLAKOGLU ◽  
ENGIN DELIGOZ
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Debye Model ◽  
First Principles Calculations ◽  
Correlation Effects ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation

The thermodynamic properties of AgB 2 and AuB 2 compounds in AlB 2 and OsB 2-type structures are investigated from first-principles calculations based on density functional theory (DFT) using projector augmented waves (PAW) potentials within the generalized gradient approximation (GGA) for modeling exchange-correlation effects, respectively. Specifically, using the quasi-harmonic Debye model, the effects of pressure and temperature, up to 100 GPa and 1400 K, on the bulk modulus, Debye temperature, thermal expansion, heat capacity and the Grüneisen parameter are calculated successfully and trends are discussed.

STRUCTURAL, MECHANICAL AND LATTICE DYNAMICAL STABILITY OF AgC AND AuC COMPOUNDS: A FIRST PRINCIPLES STUDY

2012 ◽  
Vol 26 (17) ◽  
pp. 1250107 ◽  
Author(s):  
ENGIN ATESER ◽  
HAVVA BOGAZ OZISIK
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Correlation Effects ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Dynamical Properties ◽  
Stable Structures

Based on density functional theory, we have studied the structural stability, elastic, mechanical and lattice dynamical properties of AgC and AuC compounds for various structures: NaCl ( B1 ), CsCl ( B2 ), ZnS ( B3 ), wurtzite ( B4 ), WC ( B h), NiAs ( B8 1) and CdTe . Generalized gradient approximation has been used for modeling exchange-correlation effects. The second-order elastic constants and related polycrystalline properties (bulk modulus, shear modulus, Young's modulus, Poisson's ratio, Debye temperature and sound velocities) have been calculated and discussed. We have also calculated phonon dispersion and phonon density of states of these compounds in all considered structures. According to the results, we found that, AgC compound is mechanically and dynamically stable in B8 1, B1 and B4 structures. Our results indicate that B81 and B3 are the candidate stable structures energetically, mechanically and dynamically for AgC and AuC compounds, respectively.

Theoretical study of the oxidation mechanisms of naphthalene initiated by hydroxyl radicals: the O2 addition reaction pathways

2015 ◽  
Vol 17 (20) ◽  
pp. 13719-13732 ◽  
Author(s):  
A. Shiroudi ◽  
M. S. Deleuze ◽  
S. Canneaux
Keyword(s):  
Hydroxyl Radicals ◽  
Ground State ◽  
Density Functional ◽  
Theoretical Study ◽  
Addition Reaction ◽  
Reaction Pathways ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Oxidation Mechanisms ◽  
Electronic Ground

Atmospheric oxidation of the naphthalene–OH adduct [C10H8OH]˙ (R1) by molecular oxygen in its triplet electronic ground state has been studied using density functional theory along with the B3LYP, ωB97XD, UM05-2x and UM06-2x exchange–correlation functionals.

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