Validation of density functionals for pancake-bonded π-dimers; dispersion is not enough

2017 ◽  
Vol 19 (36) ◽  
pp. 24761-24768 ◽  
Author(s):  
Zhongyu Mou ◽  
Yong-Hui Tian ◽  
Miklos Kertesz
Keyword(s):  
Density Functional ◽  
Van Der Waals ◽  
Ground States ◽  
Density Functionals ◽  
Dispersion Interactions ◽  
Π Stacking

π-Stacking pancake bonding between radicals poses special challenges to density functional theories (DFTs) due to their shorter than van der Waals contact distances, their multireference singlet ground states and the concurrently important dispersion interactions.

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

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.

Dispersion Interactions with Density-Functional Theory: Benchmarking Semiempirical and Interatomic Pairwise Corrected Density Functionals

2011 ◽  
Vol 7 (12) ◽  
pp. 3944-3951 ◽  
Author(s):  
Noa Marom ◽  
Alexandre Tkatchenko ◽  
Mariana Rossi ◽  
Vivekanand V. Gobre ◽  
Oded Hod ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functionals ◽  
Dispersion Interactions ◽  
Functional Theory

van der Waals density functionals applied to corundum-type sesquioxides: bulk properties and adsorption of CH3 and C6H6 on (0001) surfaces

2016 ◽  
Vol 18 (33) ◽  
pp. 23139-23146 ◽  
Author(s):  
Samira Dabaghmanesh ◽  
Erik C. Neyts ◽  
Bart Partoens
Keyword(s):  
Van Der Waals ◽  
Closed Shell ◽  
Accurate Description ◽  
Density Functionals ◽  
Dispersion Interactions ◽  
Bulk Properties

van der Waals treatment of the DFT functionals highlights the importance of the dispersion interactions for an accurate description of bulk properties and adsorption of open- and closed-shell molecules on sesquioxide surfaces.

scholarly journals Quantum mechanics of proteins in explicit water: The role of plasmon-like solute-solvent interactions

2019 ◽  
Vol 5 (12) ◽  
pp. eaax0024 ◽  
Author(s):  
Martin Stöhr ◽  
Alexandre Tkatchenko
Keyword(s):  
Density Functional ◽  
Van Der Waals ◽  
Tight Binding ◽  
Quantum Mechanical ◽  
Dispersion Interactions ◽  
Many Body ◽  
Biomolecular Systems ◽  
Range Interaction ◽  
Factors Affecting ◽  
Quantum Mechanical Approach

Quantum-mechanical van der Waals dispersion interactions play an essential role in intraprotein and protein-water interactions—the two main factors affecting the structure and dynamics of proteins in water. Typically, these interactions are only treated phenomenologically, via pairwise potential terms in classical force fields. Here, we use an explicit quantum-mechanical approach of density-functional tight-binding combined with the many-body dispersion formalism and demonstrate the relevance of many-body van der Waals forces both to protein energetics and to protein-water interactions. In contrast to commonly used pairwise approaches, many-body effects substantially decrease the relative stability of native states in the absence of water. Upon solvation, the protein-water dispersion interaction counteracts this effect and stabilizes native conformations and transition states. These observations arise from the highly delocalized and collective character of the interactions, suggesting a remarkable persistence of electron correlation through aqueous environments and providing the basis for long-range interaction mechanisms in biomolecular systems.

scholarly journals Evaluating dispersion forces for optimization of van der Waals complexes using a non-empirical functional

2016 ◽  
Vol 374 (2080) ◽  
pp. 20160145 ◽  
Author(s):  
Alya A. Arabi
Keyword(s):  
Density Functional ◽  
Single Point ◽  
Van Der Waals ◽  
Binding Energies ◽  
Rare Gas ◽  
Convergence Criterion ◽  
Convergence Criteria ◽  
Dispersion Interactions ◽  
Generalized Gradient ◽  
Fine Grid

Modelling dispersion interactions with traditional density functional theory (DFT) is a challenge that has been extensively addressed in the past decade. The exchange-dipole moment (XDM), among others, is a non-empirical add-on dispersion correction model in DFT. The functional PW86+PBE+XDM for exchange, correlation and dispersion, respectively, compromises an accurate functional for thermochemistry and for van der Waals (vdW) complexes at equilibrium and non-equilibrium geometries. To use this functional in optimizing vdW complexes, rather than computing single point energies, it is necessary to evaluate accurate forces. The purpose of this paper is to validate that, along the potential energy surface, the distance at which the energy is minimum is commensurate with the distance at which the forces vanish to zero. This test was validated for 10 rare gas diatomic molecules using various integration grids and different convergence criteria. It was found that the use of either convergence criterion, 10 −6 or 10 −8 , in Gaussian09, does not affect the accuracy of computed optimal distances and binding energies. An ultra-fine grid needs to be used when computing accurate energies using generalized gradient approximation functionals. This article is part of the themed issue ‘Multiscale modelling at the physics–chemistry–biology interface’.

Efficient Prediction of Structural and Electronic Properties of Hybrid 2D Materials Using DFT and Machine Learning

2018 ◽  
Author(s):  
Sherif Tawfik ◽  
Olexandr Isayev ◽  
Catherine Stampfl ◽  
Joseph Shapter ◽  
David Winkler ◽  
...  
Keyword(s):  
Machine Learning ◽  
Band Gap ◽  
Density Functional ◽  
2D Materials ◽  
Van Der Waals ◽  
Building Blocks ◽  
Machine Learning Techniques ◽  
Interlayer Distance ◽  
Computational Screening ◽  
Wide Range

Materials constructed from different van der Waals two-dimensional (2D) heterostructures offer a wide range of benefits, but these systems have been little studied because of their experimental and computational complextiy, and because of the very large number of possible combinations of 2D building blocks. The simulation of the interface between two different 2D materials is computationally challenging due to the lattice mismatch problem, which sometimes necessitates the creation of very large simulation cells for performing density-functional theory (DFT) calculations. Here we use a combination of DFT, linear regression and machine learning techniques in order to rapidly determine the interlayer distance between two different 2D heterostructures that are stacked in a bilayer heterostructure, as well as the band gap of the bilayer. Our work provides an excellent proof of concept by quickly and accurately predicting a structural property (the interlayer distance) and an electronic property (the band gap) for a large number of hybrid 2D materials. This work paves the way for rapid computational screening of the vast parameter space of van der Waals heterostructures to identify new hybrid materials with useful and interesting properties.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

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>

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