A Generally Applicable Atomic-Charge Dependent London Dispersion Correction Scheme

The D4 model is presented for the accurate computation of London dispersion interactions in density functional theory approximations (DFT-D4) and generally for atomistic modeling methods. In this successor to the DFT-D3 model, the atomic coordination-dependent dipole polarizabilities are scaled based on atomic partial charges which can be taken from various sources. For this purpose, a new charge-dependent parameter-economic scaling function is designed. Classical charges are obtained from an atomic electronegativity equilibration procedure for which efficient analytical derivatives are developed. A numerical Casimir-Polder integration of the atom-in-molecule dynamic polarizabilities yields charge- and geometry-dependent dipole-dipole dispersion coefficients. Similar to the D3 model, the dynamic polarizabilities are pre-computed by time-dependent DFT and elements up to radon are covered. For a benchmark set of 1225 dispersion coefficients, the D4 model achieves an unprecedented accuracy with a mean relative deviation of 3.8% compared to 4.7% for D3. In addition to the two-body part, three-body effects are described by an Axilrod-Teller-Muto term. A common many-body dispersion expansion was extensively tested and an energy correction based on D4 polarizabilities is found to be advantageous for some larger systems. Becke-Johnson-type damping parameters for DFT-D4 are determined for more than 60 common functionals. For various energy benchmark sets DFT-D4 slightly outperforms DFT-D3. Especially for metal containing systems, the introduced charge dependence improves thermochemical properties. We suggest (DFT-)D4 as a physically improved and more sophisticated dispersion model in place of DFT-D3 for DFT calculations as well as for other low-cost approaches like semi-empirical models.<br><br>

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A Generally Applicable Atomic-Charge Dependent London Dispersion Correction Scheme

10.26434/chemrxiv.7430216 ◽

2019 ◽

Author(s):

Eike Caldeweyher ◽

Sebastian Ehlert ◽

Andreas Hansen ◽

Hagen Neugebauer ◽

Sebastian Spicher ◽

...

Keyword(s):

Density Functional ◽

Dispersion Model ◽

Low Cost ◽

Atomic Charge ◽

Body Part ◽

Dispersion Interactions ◽

Dispersion Coefficients ◽

Charge Dependence ◽

London Dispersion ◽

Dynamic Polarizabilities

The D4 model is presented for the accurate computation of London dispersion interactions in density functional theory approximations (DFT-D4) and generally for atomistic modeling methods. In this successor to the DFT-D3 model, the atomic coordination-dependent dipole polarizabilities are scaled based on atomic partial charges which can be taken from various sources. For this purpose, a new charge-dependent parameter-economic scaling function is designed. Classical charges are obtained from an atomic electronegativity equilibration procedure for which efficient analytical derivatives are developed. A numerical Casimir-Polder integration of the atom-in-molecule dynamic polarizabilities yields charge- and geometry-dependent dipole-dipole dispersion coefficients. Similar to the D3 model, the dynamic polarizabilities are pre-computed by time-dependent DFT and elements up to radon are covered. For a benchmark set of 1225 dispersion coefficients, the D4 model achieves an unprecedented accuracy with a mean relative deviation of 3.8% compared to 4.7% for D3. In addition to the two-body part, three-body effects are described by an Axilrod-Teller-Muto term. A common many-body dispersion expansion was extensively tested and an energy correction based on D4 polarizabilities is found to be advantageous for some larger systems. Becke-Johnson-type damping parameters for DFT-D4 are determined for more than 60 common functionals. For various energy benchmark sets DFT-D4 slightly outperforms DFT-D3. Especially for metal containing systems, the introduced charge dependence improves thermochemical properties. We suggest (DFT-)D4 as a physically improved and more sophisticated dispersion model in place of DFT-D3 for DFT calculations as well as for other low-cost approaches like semi-empirical models.<br><br>

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The effect of electronic excitation on London dispersion

Canadian Journal of Chemistry ◽

10.1139/cjc-2017-0726 ◽

2018 ◽

Vol 96 (7) ◽

pp. 730-737 ◽

Cited By ~ 2

Author(s):

Xibo Feng ◽

Alberto Otero-de-la-Roza ◽

Erin R. Johnson

Keyword(s):

Density Functional ◽

Electronic Excitation ◽

Organic Dyes ◽

Dispersion Model ◽

Dispersion Energy ◽

Dispersion Coefficients ◽

Light Emitting ◽

Molecular Dispersion ◽

London Dispersion

Atomic and molecular dispersion coefficients can now be calculated routinely using density-functional theory. In this work, we present the first determination of how electronic excitation affects molecular C6 London dispersion coefficients from the exchange-hole dipole moment (XDM) dispersion model. Excited states are typically found to have larger dispersion coefficients than the corresponding ground states, due to their more diffuse electron densities. A particular focus is both intramolecular and intermolecular charge-transfer excitations, which have high absorbance intensities and are important in organic dyes, light-emitting diodes, and photovoltaics. In these classes of molecules, the increase in C6 for the electron-accepting moiety is largely offset by a decrease in C6 for the electron-donating moiety. As a result, the change in dispersion energy for a chromophore interacting with neighbouring molecules in the condensed phase is minimal.

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Application of London Dispersion Corrected Density Functional Theory for Non-Covalent Ion-π Interactions

10.26434/chemrxiv.13497135.v1 ◽

2020 ◽

Author(s):

Eike Caldeweyher ◽

Sebastian Spicher ◽

Andreas Hansen ◽

Stefan Grimme

Keyword(s):

Electrostatic Interactions ◽

Density Functional ◽

Dispersion Model ◽

Computational Cost ◽

Coupled Cluster ◽

Dispersion Interactions ◽

Field Methods ◽

Approximate Methods ◽

London Dispersion ◽

Pi Interactions

<p>The strongly attractive non-covalent interactions of charged atoms or molecules with pi-systems are important bonding motifs in many chemical and biological systems. These so-called ion-pi interactions play a major role in enzymes, molecular recognition, and for the structure of proteins. To model ion-pi interactions with DFT, it is crucial</p><p>to include London dispersion interactions, whose importance for ion-pi interactions is often underestimated. In this work, several dispersion-corrected DFT methods are evaluated for inter- and intramolecular anionic- and anion-pi interactions in larger and practically relevant molecules. We compare the DFT results with MP2, while highly</p><p>accurate (local) coupled cluster values are provided as reference. The latter can also be a great help in the development and validation of approximate methods. We demonstrate that dispersion-uncorrected DFT underestimates ion-pi interactions significantly, even though electrostatic interactions dominate the overall binding. Accordingly, the</p><p>new charge dependent D4 dispersion model is found to be consistently better than the standard D3 correction. Dispersion-corrected DFT clearly outperforms MP2/CBS whereby the best performers come close to the accuracy limit of the reference values at considerably smaller computational cost. Due to its low cost, D4 can be combined</p><p>very well with semi-empirical QM and force field methods, which is important in the development of more accurate methods for modeling large (bio)chemical systems (e.g. proteins). Another important aspect in modeling these charged systems with DFT is the self-interaction error (SIE). However, we do not find it to constitute a significant problem. Overall, the double hybrid PWPB95-D4/QZ turned out to be the most reliable among all assessed methods in predicting ion-pi interactions, which opens up new perspectives for systems where coupled cluster calculations are no longer computationally feasible.</p>

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Application of London Dispersion Corrected Density Functional Theory for Non-Covalent Ion-π Interactions

10.26434/chemrxiv.13497135 ◽

2020 ◽

Author(s):

Eike Caldeweyher ◽

Sebastian Spicher ◽

Andreas Hansen ◽

Stefan Grimme

Keyword(s):

Electrostatic Interactions ◽

Density Functional ◽

Dispersion Model ◽

Computational Cost ◽

Coupled Cluster ◽

Dispersion Interactions ◽

Field Methods ◽

Approximate Methods ◽

London Dispersion ◽

Pi Interactions

<p>The strongly attractive non-covalent interactions of charged atoms or molecules with pi-systems are important bonding motifs in many chemical and biological systems. These so-called ion-pi interactions play a major role in enzymes, molecular recognition, and for the structure of proteins. To model ion-pi interactions with DFT, it is crucial</p><p>to include London dispersion interactions, whose importance for ion-pi interactions is often underestimated. In this work, several dispersion-corrected DFT methods are evaluated for inter- and intramolecular anionic- and anion-pi interactions in larger and practically relevant molecules. We compare the DFT results with MP2, while highly</p><p>accurate (local) coupled cluster values are provided as reference. The latter can also be a great help in the development and validation of approximate methods. We demonstrate that dispersion-uncorrected DFT underestimates ion-pi interactions significantly, even though electrostatic interactions dominate the overall binding. Accordingly, the</p><p>new charge dependent D4 dispersion model is found to be consistently better than the standard D3 correction. Dispersion-corrected DFT clearly outperforms MP2/CBS whereby the best performers come close to the accuracy limit of the reference values at considerably smaller computational cost. Due to its low cost, D4 can be combined</p><p>very well with semi-empirical QM and force field methods, which is important in the development of more accurate methods for modeling large (bio)chemical systems (e.g. proteins). Another important aspect in modeling these charged systems with DFT is the self-interaction error (SIE). However, we do not find it to constitute a significant problem. Overall, the double hybrid PWPB95-D4/QZ turned out to be the most reliable among all assessed methods in predicting ion-pi interactions, which opens up new perspectives for systems where coupled cluster calculations are no longer computationally feasible.</p>

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Impact of Van der Waals interactions on structural and nonlinear optical properties of azobenzene switches

10.26434/chemrxiv.14731428.v1 ◽

2021 ◽

Author(s):

carmelo Naim ◽

Frédéric Castet ◽

Eduard Matito

Keyword(s):

Density Functional ◽

Nonlinear Optical ◽

Van Der Waals Interactions ◽

Dispersion Interactions ◽

Geometrical Structures ◽

Hartree Fock ◽

Meta Position ◽

Good Account ◽

London Dispersion ◽

Azobenzene Derivatives

<div> <div> <div> <p>The geometrical structures, relative Z-E energies, and second-order nonlinear responses of a collection of azobenzene molecules symmetrically substituted in meta- position with functional groups of different bulkiness are investigated using various ab initio and DFT levels of approximation. We show that RI-MP2 and RI-CC2 approximations provide very similar geometries and relative energies and evidence that London dispersion interactions existing between bulky meta-substituents stabilize the Z con- former. The !B97-X-D exchange-correlation functional provides an accurate description of these effects and gives a good account of the nonlinear optical response of the molecules. We show that density functional approximations should include no less than 50% of Hartree-Fock exchange to provide accurate hyperpolarizabilities. A property-structure analysis of the azobenzene derivatives reveals that the main contribution to the first hyperpolarizability comes from the azo bond, but phenyl meso-substituents can enhance it.</p> </div> </div> </div>

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Optical Properties and van der Waals-London Dispersion Interactions in Inorganic and Biomolecular Assemblies

MRS Proceedings ◽

10.1557/opl.2014.301 ◽

2014 ◽

Vol 1619 ◽

Author(s):

Daniel M. Dryden ◽

Yingfang Ma ◽

Jacob Schimelman ◽

Diana Acosta ◽

Lijia Liu ◽

...

Keyword(s):

Optical Properties ◽

Spectroscopic Ellipsometry ◽

Density Functional ◽

Type I Collagen ◽

Strong Dependence ◽

Van Der Waals ◽

Fundamental Absorption Edge ◽

Type I ◽

Dispersion Interactions ◽

London Dispersion

ABSTRACTThe optical properties and electronic structure of AlPO4, SiO2, Type I collagen, and DNA were examined to gain insight into the van der Waals-London dispersion behavior of these materials. Interband optical properties of AlPO4 and SiO2 were derived from vacuum ultraviolet spectroscopy and spectroscopic ellipsometry, and showed a strong dependence on the crystals’ constituent tetrahedral units, with strong implications for the role of phosphate groups in biological materials. The UV-Vis decadic molar absorption of four DNA oligonucleotides was measured, and showed a strong dependence on composition and stacking sequence. A film of Type I collagen was studied using spectroscopic ellipsometry, and showed a characteristic shoulder in the fundamental absorption edge at 6.05 eV. Ab initio calculations based on density functional theory corroborated the experimental results and provided further insights into the electronic structures, interband transitions and vdW-Ld interaction potentials for these materials.

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Evaluation of bismuth-based dispersion energy donors – synthesis, structure and theoretical study of 2-biphenylbismuth(iii) derivatives

Physical Chemistry Chemical Physics ◽

10.1039/c9cp06924k ◽

2020 ◽

Vol 22 (18) ◽

pp. 10189-10211

Author(s):

Ana-Maria Fritzsche ◽

Sebastian Scholz ◽

Małgorzata Krasowska ◽

Kalishankar Bhattacharyya ◽

Ana Maria Toma ◽

...

Keyword(s):

Theoretical Study ◽

Dispersion Interactions ◽

Dispersion Energy ◽

London Dispersion

Intramolecular Bi⋯π arene London dispersion interactions in (biphenyl)3−xBiXx amount to ca. 20 kJ mol−1 with distances of 3.8–4.0 Å.

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Evaluating the London Dispersion Coefficients of Protein Force Fields Using the Exchange-Hole Dipole Moment Model

10.26434/chemrxiv.6024410.v1 ◽

2018 ◽

Author(s):

Evan T. Walters ◽

Mohamad Mohebifar ◽

Erin R. Johnson ◽

Christopher Rowley

Keyword(s):

Dipole Moment ◽

Force Fields ◽

Higher Order ◽

Side Chain ◽

Dispersion Interactions ◽

Dispersion Coefficients ◽

Hydration Energies ◽

London Dispersion ◽

Higher Order Dispersion ◽

Order Dispersion

<div>London dispersion is one of the fundamental intermolecular interactions involved in protein folding and dynamics. The popular CHARMM36, Amber ff14sb, and OPLS-</div><div>AA force fields represent these interactions through the C6 /r 6 term of the Lennard-Jones potential. The C6 parameters are assigned empirically, so these parameters are</div><div>not necessarily a realistic representation of the true dispersion interactions. In this work, dispersion coefficients of all three force fields were compared to corresponding</div><div>values from quantum-chemical calculations using the exchange-hole dipole moment (XDM) model. The force field values were found to be roughly 50% larger than the XDM values for protein backbone and side-chain models. The CHARMM36 and Amber OL15 force fields for nucleic acids were also found to exhibit this trend. To explore how these elevated dispersion coefficients affect predicted properties, the hydration energies of the side-chain models were calculated using the staged REMD-TI method of Deng and Roux for the CHARMM36, Amber ff14sb, and OPLS-AA force fields. Despite having large C 6 dispersion coefficients, these force fields predict side-chain hydration energies that are in generally good agreement with the experimental values, including for hydrocarbon residues where the dispersion component is the dominant attractive solute–solvent interaction. This suggests that these force fields predict the correct total strength of dispersion interactions, despite C6 coefficients that are considerably larger than XDM predicts. An analytical expression for the water–methane dispersion energy using XDM dispersion coefficients shows that that higher-order dispersion terms(i.e., C 8 and C 10 ) account for roughly 37.5% of the hydration energy of methane. This suggests that the C 6 dispersion coefficients used in contemporary force fields are</div><div>elevated to account for the neglected higher-order terms. Force fields that include higher-order dispersion interactions could resolve this issue.</div>

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Impact of Van der Waals interactions on structural and nonlinear optical properties of azobenzene switches

10.26434/chemrxiv.14731428 ◽

2021 ◽

Author(s):

carmelo Naim ◽

Frédéric Castet ◽

Eduard Matito

Keyword(s):

Density Functional ◽

Nonlinear Optical ◽

Van Der Waals Interactions ◽

Dispersion Interactions ◽

Geometrical Structures ◽

Hartree Fock ◽

Meta Position ◽

Good Account ◽

London Dispersion ◽

Azobenzene Derivatives

<div> <div> <div> <p>The geometrical structures, relative Z-E energies, and second-order nonlinear responses of a collection of azobenzene molecules symmetrically substituted in meta- position with functional groups of different bulkiness are investigated using various ab initio and DFT levels of approximation. We show that RI-MP2 and RI-CC2 approximations provide very similar geometries and relative energies and evidence that London dispersion interactions existing between bulky meta-substituents stabilize the Z con- former. The !B97-X-D exchange-correlation functional provides an accurate description of these effects and gives a good account of the nonlinear optical response of the molecules. We show that density functional approximations should include no less than 50% of Hartree-Fock exchange to provide accurate hyperpolarizabilities. A property-structure analysis of the azobenzene derivatives reveals that the main contribution to the first hyperpolarizability comes from the azo bond, but phenyl meso-substituents can enhance it.</p> </div> </div> </div>

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