Dispersion correction for acoustic borehole logging data

2017 ◽  
Vol 142 (4) ◽  
pp. 2643-2643
Author(s):  
Said Assous ◽  
Peter Elkington
Keyword(s):  
Dispersion Correction ◽  
Borehole Logging

Minimally Empirical Double Hybrid Functionals Trained Against the GMTKN55 Database: revDSD-PBEP86-D4, revDOD-PBE-D4, and DOD-SCAN-D4

2019 ◽  
Author(s):  
Golokesh Santra ◽  
Nitai Sylvetsky ◽  
Gershom Martin
Keyword(s):  
Substantial Improvement ◽  
Viable Alternative ◽  
Mean Absolute Deviation ◽  
Dispersion Correction ◽  
Training Set ◽  
Weighted Mean ◽  
Absolute Deviation ◽  
Hybrid Functionals ◽  
Scaling Algorithms

We present a family of minimally empirical double-hybrid DFT functionals parametrized against the very large and diverse GMTKN55 benchmark. The very recently proposed wB97M(2) empirical double hybrid (with 16 empirical parameters) has the lowest WTMAD2 (weighted mean absolute deviation over GMTKN55) ever reported at 2.19 kcal/mol. However, our xrevDSD-PBEP86-D4 functional reaches a statistically equivalent WTMAD2=2.22 kcal/mol, using just a handful of empirical parameters, and the xrevDOD-PBEP86-D4 functional reaches 2.25 kcal/mol with just opposite-spin MP2 correlation, making it amenable to reduced-scaling algorithms. In general, the D4 empirical dispersion correction is clearly superior to D3BJ. If one eschews dispersion corrections of any kind, noDispSD-SCAN offers a viable alternative. Parametrization over the entire GMTKN55 dataset yields substantial improvement over the small training set previously employed in the DSD papers.

Minimally Empirical Double Hybrid Functionals Trained Against the GMTKN55 Database: revDSD-PBEP86-D4, revDOD-PBE-D4, and DOD-SCAN-D4

2019 ◽  
Author(s):  
Golokesh Santra ◽  
Nitai Sylvetsky ◽  
Gershom Martin
Keyword(s):  
Substantial Improvement ◽  
Viable Alternative ◽  
Mean Absolute Deviation ◽  
Dispersion Correction ◽  
Training Set ◽  
Weighted Mean ◽  
Absolute Deviation ◽  
Hybrid Functionals ◽  
Scaling Algorithms

We present a family of minimally empirical double-hybrid DFT functionals parametrized against the very large and diverse GMTKN55 benchmark. The very recently proposed wB97M(2) empirical double hybrid (with 16 empirical parameters) has the lowest WTMAD2 (weighted mean absolute deviation over GMTKN55) ever reported at 2.19 kcal/mol. However, our xrevDSD-PBEP86-D4 functional reaches a statistically equivalent WTMAD2=2.22 kcal/mol, using just a handful of empirical parameters, and the xrevDOD-PBEP86-D4 functional reaches 2.25 kcal/mol with just opposite-spin MP2 correlation, making it amenable to reduced-scaling algorithms. In general, the D4 empirical dispersion correction is clearly superior to D3BJ. If one eschews dispersion corrections of any kind, noDispSD-SCAN offers a viable alternative. Parametrization over the entire GMTKN55 dataset yields substantial improvement over the small training set previously employed in the DSD papers.

uMBD: A Materials-Ready Dispersion Correction that Uniformly Treats Metallic, Ionic, Covalent, and van der Waals Bonding

2019 ◽  
Author(s):  
Minho Kim ◽  
won june kim ◽  
Tim Gould ◽  
Eok Kyun Lee ◽  
Sébastien Lebègue ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Electrode Materials ◽  
Full Range ◽  
Van Der Waals ◽  
Dft Method ◽  
Dispersion Correction ◽  
Computational Overhead ◽  
System A ◽  
Battery Design

<p>Materials design increasingly relies on first-principles calculations for screening important candidates and for understanding quantum mechanisms. Density functional theory (DFT) is by far the most popular first-principles approach due to its efficiency and accuracy. However, to accurately predict structures and thermodynamics, DFT must be paired with a van der Waals (vdW) dispersion correction. Therefore, such corrections have been the subject of intense scrutiny in recent years. Despite significant successes in organic molecules, no existing model can adequately cover the full range of common materials, from metals to ionic solids, hampering the applications of DFT for modern problems such as battery design. Here, we introduce a universally optimized vdW-corrected DFT method that demonstrates an unbiased reliability for predicting molecular, layered, ionic, metallic, and hybrid materials without incurring a large computational overhead. We use our method to accurately predict the intercalation potentials of layered electrode materials of a Li-ion battery system – a problem for which the existing state-of-the-art methods fail. Thus, we envisage broad use of our method in the design of chemo-physical processes of new materials.</p>

Dispersion Correction for Split-Hopkinson Pressure Bar Data

1988 ◽  
Author(s):  
L. E. Malvern ◽  
D. A. Jenkins ◽  
E. Jerome ◽  
J. C. Gong
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Dispersion Correction ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

scholarly journals Theoretical Study of Zirconium Isomorphous Substitution into Zeolite Frameworks

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4466
Author(s):  
Duichun Li ◽  
Bin Xing ◽  
Baojun Wang ◽  
Ruifeng Li
Keyword(s):  
Acid Site ◽  
Density Functional ◽  
Theoretical Study ◽  
Atomic Radius ◽  
Acid Sites ◽  
Isomorphous Substitution ◽  
Dispersion Correction ◽  
Brønsted Acidity ◽  
Functional Theory ◽  
Brönsted Acidity

Systematic periodic density functional theory computations including dispersion correction (DFT-D) were carried out to determine the preferred location site of Zr atoms in sodalite (SOD) and CHA-type topology frameworks, including alumino-phosphate-34 (AlPO-34) and silico-alumino-phosphate-34 (SAPO-34), and to determine the relative stability and Brönsted acidity of Zr-substituted forms of SOD, AlPO-34, and SAPO-34. Mono and multiple Zr atom substitutions were considered. The Zr substitution causes obvious structural distortion because of the larger atomic radius of Zr than that of Si, however, Zr-substituted forms of zeolites are found to be more stable than pristine zeolites. Our results demonstrate that in the most stable configurations, the preferred favorable substitutions of Zr in substituted SOD have Zr located at the neighboring sites of the Al-substituted site. However, in the AlPO-34 and SAPO-34 frameworks, the Zr atoms are more easily distributed in a dispersed form, rather than being centralized. Brönsted acidity of substituted zeolites strongly depends on Zr content. For SOD, substitution of Zr atoms reduces Brönsted acidity. However, for Zr-substituted forms of AlPO-34 and SAPO-34, Brönsted acidity of the Zr-O(H)-Al acid sites are, at first, reduced and, then, the presence of Zr atoms substantially increased Brönsted acidity of the Zr-O(H)-Al acid site. The results in the SAPO-34-Zr indicate that more Zr atoms substantially increase Brönsted acidity of the Si-O(H)-Al acid site. It is suggested that substituted heteroatoms play an important role in regulating and controlling structural stability and Brönsted acidity of zeolites.

scholarly journals Modelling excited states of weakly bound complexes with density functional theory

2014 ◽  
Vol 16 (28) ◽  
pp. 14455-14462 ◽  
Author(s):  
Edward A. Briggs ◽  
Nicholas A. Besley
Keyword(s):  
Density Functional Theory ◽  
Excited States ◽  
Density Functional ◽  
Rydberg State ◽  
Dispersion Correction ◽  
Weakly Bound ◽  
Functional Theory ◽  
Weakly Bound Complexes

Different dispersion correction parameters are required to describe the interaction when the molecule is in an excited Rydberg state.

Adsorption and coadsorption of H and Li on Ag(100) surface: DFT studies including dispersion correction

2021 ◽  
pp. e00582
Author(s):  
C.C. Boungou ◽  
G.B. Bouka-Pivoteau ◽  
B.R. Malonda-Boungou ◽  
M. N’dollo ◽  
P.S. Moussounda ◽  
...  
Keyword(s):  
Dispersion Correction ◽  
Dft Studies

scholarly journals Density Functional Theory with Modified Dispersion Correction for Metals Applied to Self-Assembled Monolayers of Thiols on Au(111)

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
M. P. Andersson
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dimethyl Disulfide ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Dispersion Correction ◽  
Dissociative Chemisorption ◽  
Functional Theory ◽  
Assembled Monolayers ◽  
Self Assembled

Using sound physical principles we modify the DFT-D2 atom pairwise semiempirical dispersion correction to density functional theory to work for metallic systems and in particular self-assembled monolayers of thiols on gold surfaces. We test our approximation for two functionals PBE-D and revPBE-D for lattice parameters and cohesive energies for Ni, Pd, Pt, Cu, Ag, and Au, adsorption energies of CO on (111) surfaces of Pd, Pt, Cu, Ag, and Au, and adsorption energy of benzene on Ag(111) and Au(111). Agreement with experimental data is substantially improved. We apply the method to self-assembled monolayers of alkanethiols on Au(111) and find reasonable agreement for PBE-D and revPBE-D for both physisorption of n-alkanethiols as well as dissociative chemisorption of dimethyl disulfide as an Au-adatom-dithiolate complex. By modifying the C6 coefficient for Au, we obtain quantitative agreement for physisorption and chemisorption for both PBE-D and revPBE-D using the same set of parameters. Our results confirm that inclusion of dispersion forces is crucial for any quantitative analysis of the thiol and thiolate bonds to the gold surface using quantum chemical calculations.

Sign in / Sign up

Export Citation Format

Share Document