Application of generalized gradient-corrected density functionals to iron

1992 ◽  
Vol 46 (3) ◽  
pp. 1870-1873 ◽  
Author(s):  
Carlos Amador ◽  
Walter R. L. Lambrecht ◽  
Benjamin Segall
Keyword(s):  
Density Functionals ◽  
Generalized Gradient

scholarly journals The crystalline structure of SrRuO3: Application of hybrid scheme to the density functionals revised for solids

2017 ◽  
Vol 57 (2) ◽  
Author(s):  
Šarūnas Masys ◽  
Valdas Jonauskas
Keyword(s):  
Crystalline Structure ◽  
Density Functional ◽  
Theoretical Modelling ◽  
Density Functionals ◽  
Hybrid Scheme ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Hartree Fock ◽  
Hybrid Density Functional ◽  
Theory Scheme

The crystalline structure of ground-state orthorhombic SrRuO3 is reproduced by applying the hybrid density functional theory scheme to the functionals based on the revised generalized-gradient approximations for solidstate calculations. The amount of Hartree–Fock (HF) exchange energy is varied in the range of 5–20% in order to systematically ascertain the optimum value of HF mixing which in turn ensures the best correspondence to the experimental measurements. Such investigation allows one to expand the set of tools that could be used for the efficient theoretical modelling of, for example, only recently stabilized phases of SrRuO3, helping to resolve issues emerging for the experimentalists.

Tests of second-generation and third-generation density functionals for electron affinities of the alkylthio radicals

2014 ◽  
Vol 13 (04) ◽  
pp. 1450030 ◽  
Author(s):  
Aifang Gao ◽  
Aiguo Li
Keyword(s):  
Dft Method ◽  
Absolute Error ◽  
Molecular Structures ◽  
Basis Set ◽  
Density Functionals ◽  
Electron Affinities ◽  
Generalized Gradient ◽  
Experimental Values ◽  
P Type ◽  
Good Agreement

The molecular structures and electron affinities of the R – S / R – S -( R = CH 3, C 2 H 5, n- C 3 H 7, n- C 4 H 9, n- C 5 H 11, i- C 3 H 7, i- C 4 H 9, t- C 4 H 9) species have been studied using 17 pure and hybrid density functionals (five generalized gradient approximation (GGA) methods, six hybrid GGAs, one meta GGA method and five hybrid meta GGAs). The basis set used in this work is of double-ζ plus polarization quality with additional diffuse s- and p-type functions, denoted by DZP++. The geometries are fully optimized with each DFT method and discussed. Harmonic vibrational frequencies are found to be within 3.5% of available experimental values for most functionals. Three different types of the neutral-anion energy separations have been presented. The theoretical electron affinities of alkylthio radicals are in good agreement with the experiment data. The M06 method is very good for the adiabatic electron affinity calculations, and the average absolute error is 0.0439 eV. The HCTH method performs better for EA prediction. The M06-HF, mPWPW91, VSXC and B98 are also reasonable. The most reliable adiabatic electron affinities are predicted to be 1.864 eV ( CH 3 S ), 1.946 eV ( C 2 H 5 S ), 1.959 eV (n- C 3 H 7 S ), 1.970 eV (n- C 4 H 9 S ), 1.982 eV (n- C 5 H 11 S ), 2.053 eV (i- C 3 H 7 S ), 1.991 eV (i- C 4 H 9 S ) and 2.100 eV (t- C 4 H 9 S ) at the M06/DZP++ level of theory, respectively.

scholarly journals Coulomb Energy Density Functionals for Nuclear Systems: Recent Studies of Coulomb Exchange and Correlation Functionals

2019 ◽  
Vol 223 ◽  
pp. 01044
Author(s):  
Tomoya Naito ◽  
Ryosuke Akashi ◽  
Gianluca Colò ◽  
Haozhao Liang ◽  
Xavier Roca-Maza
Keyword(s):  
Energy Density ◽  
Nuclear Force ◽  
Correlation Energy ◽  
Coulomb Energy ◽  
Density Functionals ◽  
Electron Systems ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation ◽  
Nuclear Systems ◽  
Exchange And Correlation

The Coulomb exchange and correlation energy density functionals for electron systems are applied to nuclearsystems. It is found that the exchange functionals in the generalized gradient approximation provide agreements with the exact-Fock energy with one adjustable parameter within a few dozen keV accuracy, whereas the correlation functionals are not directly applicable to nuclear systems due to the existence of the nuclear force.

scholarly journals General Many-Body Framework for Data-Driven Potentials with Arbitrary Quantum Mechanical Accuracy: Water as a Case Study

2021 ◽  
Author(s):  
Eleftherios Lambros ◽  
Saswata Dasgupta ◽  
Etienne Palos ◽  
Steven Swee ◽  
Jie Hu ◽  
...  
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Water Clusters ◽  
Data Driven ◽  
Quantum Mechanical ◽  
Density Functionals ◽  
Many Body ◽  
Generalized Gradient ◽  
Systematic Analysis ◽  
Arbitrary Quantum

<div> <div> <div> <p> </p><div> <div> <div> <p>We present a general framework for the development of data-driven many-body (MB) potential energy functions (MB-QM PEFs) that represent the interactions between small molecules at an arbitrary quantum-mechanical (QM) level of theory. As a demonstration, a family of MB-QM PEFs for water are rigorously derived from density functionals belonging to differ- ent rungs across Jacob’s ladder of approximations within density functional theory (MB-DFT) as well as from Møller-Plesset perturbation theory (MB-MP2). Through a systematic analysis of individual many-body contributions to the interaction energies of water clusters, we demonstrate that all MB-QM PEFs preserve the same accuracy as the corresponding ab initio calculations, with the exception of those derived from density functionals within the generalized gradient approximation (GGA). The differences between the DFT and MB-DFT results are traced back to density-driven errors that prevent GGA functionals from accurately representing the underlying molecular interactions for different cluster sizes and hydrogen-bonding arrangements. We show that this shortcoming may be overcome, within the many-body formalism, by using density-corrected functionals that provide a more consistent representation of each individual many-body contribution. This is demonstrated through the development of a MB-DFT PEF derived from density-corrected PBE-D3 data, which more accurately reproduce the corresponding ab initio results. </p> </div> </div> </div> </div> </div> </div>

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