نتایج جستجو برای: gga

تعداد نتایج: 1640  

Journal: :The journal of physical chemistry. A 2005
Nathan E Schultz Yan Zhao Donald G Truhlar

We present a database of 21 bond dissociation energies for breaking metal-ligand bonds. The molecules in the metal-ligand bond energy database are AgH, CoH, CoO+, CoOH+, CrCH3+, CuOH2+, FeH, Fe(CO)5, FeO, FeS, LiCl, LiO, MgO, MnCH3NiCH2+, Ni(CO)4, RhC, VCO+, VO, and VS. We have also created databases of metal-ligand bond lengths and atomic ionization potentials. The molecules used for bond leng...

Journal: :npj computational materials 2022

Abstract Computational materials discovery efforts are enabled by large databases of properties derived from high-throughput density functional theory (DFT), which now contain millions calculations at the generalized gradient approximation (GGA) level theory. It is feasible to carry out using more accurate methods, such as meta-GGA DFT; however recomputing an entire database with a higher-fidel...

Journal: :Theoretical Chemistry Accounts 2023

DFT reactivity descriptors, the ultraviolet–visible spectra and hydrolysis mechanism of three cationic dyes [Malachite Green (MG), Brilliant (BG) Ethyl (EG)] are performed with several exchange–correlation functional (global GGA, hybrids range-separated). Using time-dependent density theory, theoretical absorption obtained obey trend for λmax: GGA > hybrid range-separated functional. Thanks to ...

جلالی اسدآبادی, سعید, خردمند, فاطمه ,

 In this work structural, electronic and magnetic properties of alpha and gamma phases of cerium crystal have been calculated by means of the LDA and LDA+U methods. The equilibrium volume and magnetic moment obtained from the GGA approximation in agreement with the experiment are equal to 27.64 Å3 and 0.00018 µB, respectively. This agreement shows that the 4f electrons in alpha phase are itiner...

1999
W.-K. Leung R. J. Needs G. Rajagopal

We report a theoretical study of self-interstitial defects in silicon using local density approximation (LDA), PW91 generalized gradient approximation (GGA), and fixed-node diffusion quantum Monte Carlo (DMC) methods. The formation energies of the stablest interstitial defects are about 3.3 eV within the LDA, 3.8 eV within the PW91-GGA, and 4.9 eV within DMC. The DMC results indicate a value fo...

2004
R. Caracas R. Wentzcovitch

[1] FeSi may be one of the main products of the reaction between molten iron and mantle silicates. We use both the Local Density Approximation (LDA) and the Generalized Gradient Approximation (GGA) to Density Functional Theory (DFT) to analyze the structural behavior of FeSi and to determine its elastic properties up to high pressures. According to our calculations, at lowermost mantle pressure...

1999
John P. Perdew Stefan Kurth Aleš Zupan Peter Blaha

We approximate the exchange-correlation energy of density functional theory as a controlled extrapolation from the slowly varying limit. While generalized gradient approximations (GGA’s) require only the local density and its first gradient as input, our meta-GGA also requires the orbital kinetic energy density. Its exchange energy component recovers the fourth-order gradient expansion, while i...

1997
Robert Kouba Claudia Ambrosch-Draxl

We report first–principles frozen–phonon calculations for the determination of the force–free geometry and the dynamical matrix of the five Raman–active A1g modes in YBa2Cu3O7. To establish the shape of the phonon potentials atomic forces are calculated within the LAPWmethod. Two different schemes – the local density approximation (LDA) and a generalized gradient approximation (GGA) – are emplo...

Journal: :Anales AFA 2021

We present here a first principles study of the structural, electronic, magnetic, and hyperfine properties magnesium ferrite, MgFe2O4 (spinel structure). The was carried out within framework Functional Density Theory (DFT) using full potential linearized augmented plane waves method (FPLAPW) both Generalized Gradient (GGA) GGA+U approximations for exchange correlation potential. To discuss magn...

Journal: :Physical review letters 2009
John P Perdew Adrienn Ruzsinszky Gábor I Csonka Lucian A Constantin Jianwei Sun

Semilocal density functionals for the exchange-correlation energy are needed for large electronic systems. The Tao-Perdew-Staroverov-Scuseria (TPSS) meta-generalized gradient approximation (meta-GGA) is semilocal and usefully accurate, but predicts too-long lattice constants. Recent "GGA's for solids" yield good lattice constants but poor atomization energies of molecules. We show that the cons...

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