scholarly journals On the Many-Body Expansion of an Interaction Energy of Some Supramolecular Halogen-Containing Capsules

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4431
Author(s):  
Jiří Czernek ◽  
Jiří Brus
Keyword(s):  
Density Functional ◽  
Condensed Phases ◽  
Multicomponent Mixtures ◽  
Many Body ◽  
Symmetric Form ◽  
Functional Theory ◽  
Emergent Features ◽  
The Many ◽  
Surprising Fact ◽  
Dimethyl Benzene

A tetramer model was investigated of a remarkably stable iodine-containing supramolecular capsule that was most recently characterized by other authors, who described emergent features of the capsule’s formation. In an attempt to address the surprising fact that no strong pair-wise interactions between any of the respective components were experimentally detected in condensed phases, the DFT (density-functional theory) computational model was used to decompose the total stabilization energy as a sum of two-, three- and four-body contributions. This model considers complexes formed between either iodine or bromine and the crucial D4h-symmetric form of octaaryl macrocyclic compound cyclo[8](1,3-(4,6-dimethyl)benzene that is surrounded by arenes of a suitable size, namely, either corannulene or coronene. A significant enthalpic gain associated with the formation of investigated tetramers was revealed. Furthermore, it is shown that the total stabilization of these complexes is dominated by binary interactions. Based on these findings, comments are made regarding the experimentally observed behavior of related multicomponent mixtures.

scholarly journals Including dispersion in density functional theory for adsorption on flat oxide surfaces, in metal–organic frameworks and in acidic zeolites

2020 ◽  
Vol 22 (14) ◽  
pp. 7577-7585 ◽  
Author(s):  
Florian R. Rehak ◽  
GiovanniMaria Piccini ◽  
Maristella Alessio ◽  
Joachim Sauer
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Van Der Waals ◽  
Metal Organic Frameworks ◽  
Many Body ◽  
Functional Theory ◽  
Metal Organic ◽  
The Many ◽  
Acidic Zeolites ◽  
Better Than

Contrary to common believe, for eight adsorption cases, neither D3 or TS are an improvement compared to D2 nor van der Waals functionals or dDsC. Only the many body approaches are slightly better than D2(Ne) which uses Ne parameters for Mg2+ ions.

scholarly journals Frozen-Density Embedding Based Many-Body Expansions

2020 ◽  
Author(s):  
Daniel Schmitt-Monreal ◽  
Christoph R. Jacob
Keyword(s):  
Density Functional ◽  
Molecular Clusters ◽  
Test Case ◽  
Chemical Calculation ◽  
Many Body ◽  
Functional Theory ◽  
Truncation Errors ◽  
Potential Benefits ◽  
The Many ◽  
The One

<div>Fragmentation methods allow for the accuratequantum-chemical treatment of large molecular clusters and materials. Here, we explore the combination of two complementary approaches to the development of such fragmentation methods: the many-body expansion (MBE) on the one hand and subsystem density-functional theory (DFT) or frozen-density embedding (FDE) theory on the other hand. First, we assess potential benefits of using FDE to account of the environmentin the subsystem calculation performed within the MBE. Second, we use subsystem DFT to derive a density-based MBE, in which a many-body expansion of the electron density is used to calculate the systems' total energy. This provides a correctionto the energies calculated with a conventional, energy-based MBE that only depends on the subsystem's electron densities. For the test case of clusters of water and of aspirin, we show that such a density-based MBE converges faster than the conventional energy-based MBE. For our test cases, truncation errors in the interaction energies are below chemical accuracy already with a two-body expansion. The density-based MBE thus provides a promising avenue for accurate quantum-chemical calculation of molecular clusters and materials.</div>

scholarly journals O(N)Stochastic Evaluation of Many-Body van der Waals Energies in Large Complex Systems

2021 ◽  
Author(s):  
Pier Paolo Poier ◽  
Louis Lagardère ◽  
Jean-Philip Piquemal
Keyword(s):  
Density Functional ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Complex Materials ◽  
Many Body ◽  
Functional Theory ◽  
Molecular Systems ◽  
New Strategy ◽  
The Many ◽  
Van Der Waals Energies

We propose a new strategy to solve the Tkatchenko-Scheffler Many-Body Dispersion (MBD) model’s equations. Our approach overcomes the original O(N**3) computational complexity that limits its applicability to large molecular systems within thecontext of O(N) Density Functional Theory (DFT). First, in order to generate the required frequency-dependent screenedpolarizabilities, we introduce an efficient solution to the Dyson-like self-consistent screening equations. The scheme reducesthe number of variables and, coupled to a DIIS extrapolation, exhibits linear-scaling performances. Second, we apply astochastic Lanczos trace estimator resolution to the equations evaluating the many-body interaction energy of coupled quantumharmonic oscillators. While scaling linearly, it also enables communication-free pleasingly-parallel implementations. As the resulting O(N) stochastic massively parallel MBD approach is found to exhibit minimal memory requirements, it opens up the possibility of computing accurate many-body van der Waals interactions of millions-atoms’ complex materials and solvated biosystems with computational times in the range of minutes.

SELF-ENERGY REVISION OPERATOR THEORY FOR THE MANY-BODY PROBLEM: APPLICATION TO DYNAMICAL PROPERTIES OF THE ELECTRON GAS

2001 ◽  
Vol 15 (19n20) ◽  
pp. 2595-2610 ◽  
Author(s):  
YASUTAMI TAKADA
Keyword(s):  
Density Functional ◽  
Body Problem ◽  
Dynamic Properties ◽  
Electron Gas ◽  
Many Body ◽  
Functional Theory ◽  
Correlation Kernel ◽  
Exchange Correlation ◽  
Self Energy ◽  
The Many

An approximation scheme is proposed for implementing the algorithm to obtain the exact self-energy in the many-body problem [Phys. Rev.B52, 12708 (1995)]. This scheme relates the self-energy revision operator ℱ, the key quantity in the algorithm, with fxc(q,ω) the frequency-dependent exchange-correlation kernel appearing in the time-dependent density functional theory. We illustrate this scheme by applying it to the calculation of dynamic properties of the electron gas at metallic densities.

Frozen-Density Embedding Based Many-Body Expansions

2020 ◽  
Author(s):  
Daniel Schmitt-Monreal ◽  
Christoph R. Jacob
Keyword(s):  
Density Functional ◽  
Molecular Clusters ◽  
Test Case ◽  
Chemical Calculation ◽  
Many Body ◽  
Functional Theory ◽  
Truncation Errors ◽  
Potential Benefits ◽  
The Many ◽  
The One

<div>Fragmentation methods allow for the accuratequantum-chemical treatment of large molecular clusters and materials. Here, we explore the combination of two complementary approaches to the development of such fragmentation methods: the many-body expansion (MBE) on the one hand and subsystem density-functional theory (DFT) or frozen-density embedding (FDE) theory on the other hand. First, we assess potential benefits of using FDE to account of the environmentin the subsystem calculation performed within the MBE. Second, we use subsystem DFT to derive a density-based MBE, in which a many-body expansion of the electron density is used to calculate the systems' total energy. This provides a correctionto the energies calculated with a conventional, energy-based MBE that only depends on the subsystem's electron densities. For the test case of clusters of water and of aspirin, we show that such a density-based MBE converges faster than the conventional energy-based MBE. For our test cases, truncation errors in the interaction energies are below chemical accuracy already with a two-body expansion. The density-based MBE thus provides a promising avenue for accurate quantum-chemical calculation of molecular clusters and materials.</div>

Density Functional Theory

2017 ◽  
Author(s):  
Olle Eriksson ◽  
Anders Bergman ◽  
Lars Bergqvist ◽  
Johan Hellsvik
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Effective Theory ◽  
Many Body ◽  
Functional Theory ◽  
Sham Equation ◽  
Magnetic Solid ◽  
Properties Of Materials ◽  
The Many

Density functional theory (DFT) has established itself as a very capable platform for modelling from first principles electronic, optical, mechanical and structural properties of materials. Starting out from the Dirac equation for the many-body system of electrons and nuclei, an effective theory has been developed allowing for materials specific and parameter free simulations of non-magnetic and magnetic solid matter. In this Chapter an introduction will be given to DFT, the Hohenberg-Kohn theorems, the Kohn-Sham equation, and the formalism for how to deal with non-collinear magnetism.

scholarly journals O(N)Stochastic Evaluation of Many-Body van der Waals Energies in Large Complex Systems

2021 ◽  
Author(s):  
Pier Paolo Poir ◽  
Louis Lagardère ◽  
Jean-Philip Piquemal
Keyword(s):  
Density Functional ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Complex Materials ◽  
Many Body ◽  
Functional Theory ◽  
Molecular Systems ◽  
New Strategy ◽  
The Many ◽  
Van Der Waals Energies

We propose a new strategy to solve the Tkatchenko-Scheffler Many-Body Dispersion (MBD) model’s equations. Our approach overcomes the original O(N**3) computational complexity that limits its applicability to large molecular systems within thecontext of O(N) Density Functional Theory (DFT). First, in order to generate the required frequency-dependent screenedpolarizabilities, we introduce an efficient solution to the Dyson-like self-consistent screening equations. The scheme reducesthe number of variables and, coupled to a DIIS extrapolation, exhibits linear-scaling performances. Second, we apply astochastic Lanczos trace estimator resolution to the equations evaluating the many-body interaction energy of coupled quantumharmonic oscillators. While scaling linearly, it also enables communication-free pleasingly-parallel implementations. As the resulting O(N) stochastic massively parallel MBD approach is found to exhibit minimal memory requirements, it opens up the possibility of computing accurate many-body van der Waals interactions of millions-atoms’ complex materials and solvated biosystems with computational times in the range of minutes.

scholarly journals Frozen-Density Embedding Based Many-Body Expansions

2020 ◽  
Author(s):  
Daniel Schmitt-Monreal ◽  
Christoph R. Jacob
Keyword(s):  
Density Functional ◽  
Molecular Clusters ◽  
Test Case ◽  
Chemical Calculation ◽  
Many Body ◽  
Functional Theory ◽  
Truncation Errors ◽  
Potential Benefits ◽  
The Many ◽  
The One

<div>Fragmentation methods allow for the accuratequantum-chemical treatment of large molecular clusters and materials. Here, we explore the combination of two complementary approaches to the development of such fragmentation methods: the many-body expansion (MBE) on the one hand and subsystem density-functional theory (DFT) or frozen-density embedding (FDE) theory on the other hand. First, we assess potential benefits of using FDE to account of the environmentin the subsystem calculation performed within the MBE. Second, we use subsystem DFT to derive a density-based MBE, in which a many-body expansion of the electron density is used to calculate the systems' total energy. This provides a correctionto the energies calculated with a conventional, energy-based MBE that only depends on the subsystem's electron densities. For the test case of clusters of water and of aspirin, we show that such a density-based MBE converges faster than the conventional energy-based MBE. For our test cases, truncation errors in the interaction energies are below chemical accuracy already with a two-body expansion. The density-based MBE thus provides a promising avenue for accurate quantum-chemical calculation of molecular clusters and materials.</div>

scholarly journals Comparing many-body approaches against the helium atom exact solution

2019 ◽  
Vol 6 (4) ◽  
Author(s):  
Jing Li ◽  
N. D. Drummond ◽  
Peter Schuck ◽  
Valerio Olevano
Keyword(s):  
Exact Solution ◽  
Helium Atom ◽  
Quantum Monte Carlo ◽  
Nuclear Physics ◽  
Density Functional ◽  
Random Phase ◽  
Basis Set ◽  
Many Body ◽  
Functional Theory ◽  
The Many

Over time, many different theories and approaches have been developed to tackle the many-body problem in quantum chemistry, condensed-matter physics, and nuclear physics. Here we use the helium atom, a real system rather than a model, and we use the exact solution of its Schrödinger equation as a benchmark for comparison between methods. We present new results beyond the random-phase approximation (RPA) from a renormalized RPA (r-RPA) in the framework of the self-consistent RPA (SCRPA) originally developed in nuclear physics, and compare them with various other approaches like configuration interaction (CI), quantum Monte Carlo (QMC), time-dependent density-functional theory (TDDFT), and the Bethe-Salpeter equation on top of the \boldsymbol{GW}𝐆𝐖 approximation. Most of the calculations are consistently done on the same footing, e.g. using the same basis set, in an effort for a most faithful comparison between methods.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

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