scholarly journals Elevating Density Functional Theory to Chemical Accuracy for Water Simulations through a Density-Corrected Many-Body Formalism

2021 ◽  
Author(s):  
Saswata Dasgupta ◽  
Eleftherios Lambros ◽  
John Perdew ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Water Clusters ◽  
Potential Energy Function ◽  
Data Driven ◽  
Coupled Cluster ◽  
Many Body ◽  
Functional Theory ◽  
Dynamics Simulations ◽  
Body Potential

Density functional theory (DFT) has been extensively used to model the properties of water. Albeit maintaining a good balance between accuracy and efficiency, no density functional has so far achieved the degree of accuracy necessary to correctly predict the properties of water across the entire phase diagram. Here, we present density-corrected SCAN (DC-SCAN) calculations for water which, minimizing density-driven errors, elevate the accuracy of the SCAN functional to that of “gold standard” coupled-cluster theory. Building upon the accuracy of DC-SCAN within a many-body formalism, we introduce a data-driven many-body potential energy function, MB-SCAN(DC), that quantitatively reproduces coupled cluster reference values for interaction, binding, and individual many-body energies of water clusters. Importantly, molecular dynamics simulations carried out with MB-SCAN(DC) also reproduce the properties of liquid water, which thus demonstrates that MB-SCAN(DC) is effectively the first DFT-based model that correctly describes water from the gas to the liquid phase.

scholarly journals Elevating density functional theory to chemical accuracy for water simulations through a density-corrected many-body formalism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Saswata Dasgupta ◽  
Eleftherios Lambros ◽  
John P. Perdew ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Water Clusters ◽  
Potential Energy Function ◽  
Data Driven ◽  
Coupled Cluster ◽  
Many Body ◽  
Functional Theory ◽  
Dynamics Simulations ◽  
Body Potential

AbstractDensity functional theory (DFT) has been extensively used to model the properties of water. Albeit maintaining a good balance between accuracy and efficiency, no density functional has so far achieved the degree of accuracy necessary to correctly predict the properties of water across the entire phase diagram. Here, we present density-corrected SCAN (DC-SCAN) calculations for water which, minimizing density-driven errors, elevate the accuracy of the SCAN functional to that of “gold standard” coupled-cluster theory. Building upon the accuracy of DC-SCAN within a many-body formalism, we introduce a data-driven many-body potential energy function, MB-SCAN(DC), that quantitatively reproduces coupled cluster reference values for interaction, binding, and individual many-body energies of water clusters. Importantly, molecular dynamics simulations carried out with MB-SCAN(DC) also reproduce the properties of liquid water, which thus demonstrates that MB-SCAN(DC) is effectively the first DFT-based model that correctly describes water from the gas to the liquid phase.

STRUCTURAL AND ELECTRONIC PROPERTIES OF CARBON NANOBALLS: C20, C60, AND C20@C60

2001 ◽  
Vol 12 (09) ◽  
pp. 1391-1399 ◽  
Author(s):  
ŞAKIR ERKOÇ ◽  
LEMI TÜRKER
Keyword(s):  
Heat Treatment ◽  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Density Functional ◽  
Potential Energy Function ◽  
Many Body ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Type C ◽  
Body Potential

The structural stability of carbon nanoballs (fullerenes) C 20, C 60, and onion type C 20@ C 60 has been investigated by performing molecular-dynamics computer simulations. Calculations have been realized by using an empirical many-body potential energy function for carbon. It has been found that C 20 is relatively resistive to heat treatment, however, the onion type structure is relatively less strong against heat treatment. The electronic structure of the systems considered has been also studied by performing density functional theory type calculations.

Investigation of structural and energetic behavior of 55-atom Pt–Ag–Au ternary nanoalloys

2021 ◽  
pp. 2150174
Author(s):  
Hüseyin Yıldırım ◽  
Ali Kemal Garip
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Analysis ◽  
Many Body ◽  
Functional Theory ◽  
Mixing Energy ◽  
Chemical Ordering ◽  
The One ◽  
Body Potential ◽  
Basin Hopping

A systematic theoretical investigation of structural and energetic behaviors of 55-atom Pt–Ag–Au ternary nanoalloys has been performed in two different composition systems. We have performed Gupta and Density Functional Theory (DFT) approaches on chosen systems. The Basin-Hopping algorithm is used for structural optimizations of PtnAg[Formula: see text]Au[Formula: see text] ([Formula: see text]–13) and PtnAu[Formula: see text]Ag[Formula: see text] ([Formula: see text]–13) ternary nanoalloys with Gupta many-body potential to model interatomic interactions. Local optimization results show that while the tendency of Au atoms to be located varies according to the composition system, the tendency of Pt and Ag atoms to be located does not change in both. For all compositions of Pt–Ag–Au nanoalloys, the structures with the best chemical ordering were then reoptimized by DFT relaxations and the mixing energies of the Gupta and DFT levels were compared. Our mixing energy analysis showed that PtnAg[Formula: see text]Au[Formula: see text] ([Formula: see text]–13) nanoalloys are not energetically suitable for mixing at both Gupta and DFT level. Also, mixing energy variations of PtnAu[Formula: see text]Ag[Formula: see text] ([Formula: see text]–13) nanoalloys obtained at Gupta level does not agree with the one obtained at DFT level. In addition, it has been found that the minimization energy changes when an atom in the central site is exchanging by an atom in the second shell and surface.

scholarly journals Highly Accurate Many-Body Potentials for Simulations of N2O5 in Water: Benchmarks, Development, and Validation

2021 ◽  
Author(s):  
Vinicius Cruzeiro ◽  
Eleftherios Lambros ◽  
Marc Riera ◽  
Ronak Roy ◽  
Francesco Paesani ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Atmospheric Chemistry ◽  
Short Range ◽  
Density Functional ◽  
Coupled Cluster ◽  
Many Body ◽  
Functional Theory ◽  
High Level ◽  
Three Body ◽  
Many Body Interactions

<div><div><div><p>Dinitrogen pentoxide (N2O5) is an important intermediate in the atmospheric chemistry of nitrogen oxides. Although there has been much research, the processes that govern the physical interactions between N2O5 and water are still not fully understood at a molecular level. Gaining quantitative insight from computer simulations requires going beyond the accuracy of classical force fields, while accessing length scales and time scales that are out of reach for high-level quantum chemical approaches. To this end we present the development of MB-nrg many-body potential energy functions for simulations of N2O5 in water. This MB-nrg model is based on electronic structure calculations at the coupled cluster level of theory and is compatible with the successful MB-pol model for water. It provides a physically correct description of long-range many-body interactions in combination with an explicit representation of up to three-body short-range interactions in terms of multidimensional permutationally invariant polynomials. In order to further investigate the importance of the underlying interactions in the model, a TTM-nrg model was also devised. TTM- nrg is a more simplistic representation that contains only two-body short-range interactions represented through Born-Mayer functions. In this work an active learning approach was employed to efficiently build representative training sets of monomer, dimer and trimer structures, and benchmarks are presented to determine the accuracy of our new models in comparison to a range of density functional theory methods. By assessing binding curves, distortion energies of N2O5, and interaction energies in clusters of N2O5 and water, we evaluate the importance of two-body and three-body short-range potentials. The results demonstrate that our MB-nrg model has high accuracy with respect to the coupled cluster reference, outperforms current density functional theory models, and thus enables highly accurate simulations of N2O5 in aqueous environments.</p></div></div></div>

scholarly journals Highly Accurate Many-Body Potentials for Simulations of N2O5 in Water: Benchmarks, Development, and Validation

2021 ◽  
Author(s):  
Vinicius Cruzeiro ◽  
Eleftherios Lambros ◽  
Marc Riera ◽  
Ronak Roy ◽  
Francesco Paesani ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Atmospheric Chemistry ◽  
Short Range ◽  
Density Functional ◽  
Coupled Cluster ◽  
Many Body ◽  
Functional Theory ◽  
High Level ◽  
Three Body ◽  
Many Body Interactions

<div><div><div><p>Dinitrogen pentoxide (N2O5) is an important intermediate in the atmospheric chemistry of nitrogen oxides. Although there has been much research, the processes that govern the physical interactions between N2O5 and water are still not fully understood at a molecular level. Gaining quantitative insight from computer simulations requires going beyond the accuracy of classical force fields, while accessing length scales and time scales that are out of reach for high-level quantum chemical approaches. To this end we present the development of MB-nrg many-body potential energy functions for simulations of N2O5 in water. This MB-nrg model is based on electronic structure calculations at the coupled cluster level of theory and is compatible with the successful MB-pol model for water. It provides a physically correct description of long-range many-body interactions in combination with an explicit representation of up to three-body short-range interactions in terms of multidimensional permutationally invariant polynomials. In order to further investigate the importance of the underlying interactions in the model, a TTM-nrg model was also devised. TTM- nrg is a more simplistic representation that contains only two-body short-range interactions represented through Born-Mayer functions. In this work an active learning approach was employed to efficiently build representative training sets of monomer, dimer and trimer structures, and benchmarks are presented to determine the accuracy of our new models in comparison to a range of density functional theory methods. By assessing binding curves, distortion energies of N2O5, and interaction energies in clusters of N2O5 and water, we evaluate the importance of two-body and three-body short-range potentials. The results demonstrate that our MB-nrg model has high accuracy with respect to the coupled cluster reference, outperforms current density functional theory models, and thus enables highly accurate simulations of N2O5 in aqueous environments.</p></div></div></div>

On the Nature of Halide-Water Interactions: Insights from Many-Body Representations and Density Functional Theory

2019 ◽  
Author(s):  
Brandon B. Bizzarro ◽  
Colin K. Egan ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Molecular Orbital ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Orbital Energy ◽  
Energy Decomposition Analysis ◽  
Interaction Energies ◽  
Many Body ◽  
Functional Theory

<div> <div> <div> <p>Interaction energies of halide-water dimers, X<sup>-</sup>(H<sub>2</sub>O), and trimers, X<sup>-</sup>(H<sub>2</sub>O)<sub>2</sub>, with X = F, Cl, Br, and I, are investigated using various many-body models and exchange-correlation functionals selected across the hierarchy of density functional theory (DFT) approximations. Analysis of the results obtained with the many-body models demonstrates the need to capture important short-range interactions in the regime of large inter-molecular orbital overlap, such as charge transfer and charge penetration. Failure to reproduce these effects can lead to large deviations relative to reference data calculated at the coupled cluster level of theory. Decompositions of interaction energies carried out with the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method demonstrate that permanent and inductive electrostatic energies are accurately reproduced by all classes of XC functionals (from generalized gradient corrected (GGA) to hybrid and range-separated functionals), while significant variance is found for charge transfer energies predicted by different XC functionals. Since GGA and hybrid XC functionals predict the most and least attractive charge transfer energies, respectively, the large variance is likely due to the delocalization error. In this scenario, the hybrid XC functionals are then expected to provide the most accurate charge transfer energies. The sum of Pauli repulsion and dispersion energies are the most varied among the XC functionals, but it is found that a correspondence between the interaction energy and the ALMO EDA total frozen energy may be used to determine accurate estimates for these contributions. </p> </div> </div> </div>

Reciprocal Polarizable Embedding with a Transferable H2O Potential Function II: Application to (H2O)n Clusters & Liquid Water

2019 ◽  
Author(s):  
Asmus Ougaard Dohn ◽  
Elvar Jónsson ◽  
Hannes Jonsson
Keyword(s):  
Density Functional Theory ◽  
Liquid Water ◽  
Density Functional ◽  
Water Clusters ◽  
Theory Model ◽  
Coupling Scheme ◽  
Functional Theory ◽  
Total Polarization ◽  
Electrostatic Embedding ◽  
Polarizable Embedding

The manuscript analyzes the accuracy of our recently developed reciprocal polarizable embedding scheme, where a density functional theory model of the QM region is coupled to a dipole- and quadrupole polarizable water potential of the MM region. We present calculations of water clusters and liquid water where we analyze the energy, atomic forces and total polarization to demonstrate that artifacts in energy and polarization introduced by the QM/MM coupling are small and well-behaved. Furthermore, our methodology improves the consistency of the structure of optimized water hexamer geometries when compared to results obtained with models that neglect polarization. Additionally, the manuscript provides evidence that our coupling scheme eliminates artifacts in the structure of liquid water obtained with simpler electrostatic embedding models.

Sign in / Sign up

Export Citation Format

Share Document