Subsystem density-functional theory as an effective tool for modeling ground and excited states, their dynamics and 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>

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Excited states properties of organic molecules: from density functional theory to the GW and Bethe–Salpeter Green's function formalisms

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2013.0271 ◽

2014 ◽

Vol 372 (2011) ◽

pp. 20130271 ◽

Cited By ~ 72

Author(s):

C. Faber ◽

P. Boulanger ◽

C. Attaccalite ◽

I. Duchemin ◽

X. Blase

Keyword(s):

Density Functional Theory ◽

Green’S Function ◽

Excited States ◽

Green's Function ◽

Potential Energy Surfaces ◽

Density Functional ◽

Many Body ◽

Excitation Energies ◽

Functional Theory ◽

Organic Systems

Many-body Green's function perturbation theories, such as the GW and Bethe–Salpeter formalisms, are starting to be routinely applied to study charged and neutral electronic excitations in molecular organic systems relevant to applications in photovoltaics, photochemistry or biology. In parallel, density functional theory and its time-dependent extensions significantly progressed along the line of range-separated hybrid functionals within the generalized Kohn–Sham formalism designed to provide correct excitation energies. We give an overview and compare these approaches with examples drawn from the study of gas phase organic systems such as fullerenes, porphyrins, bacteriochlorophylls or nucleobases molecules. The perspectives and challenges that many-body perturbation theory is facing, such as the role of self-consistency, the calculation of forces and potential energy surfaces in the excited states, or the development of embedding techniques specific to the GW and Bethe–Salpeter equation formalisms, are outlined.

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

10.26434/chemrxiv.13613678.v1 ◽

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>

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

10.26434/chemrxiv.7613042.v2 ◽

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>

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Global double hybrids do not work for charge transfer: A comment on “Double hybrids and time‐dependent density functional theory: An implementation and benchmark on charge transfer excited states”

Journal of Computational Chemistry ◽

10.1002/jcc.26478 ◽

2021 ◽

Vol 42 (8) ◽

pp. 528-533

Author(s):

Marcos Casanova‐Páez ◽

Lars Goerigk

Keyword(s):

Density Functional Theory ◽

Charge Transfer ◽

Excited States ◽

Density Functional ◽

Time Dependent ◽

Functional Theory ◽

Dependent Density

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Analytic gradients for multiconfiguration pair-density functional theory with density fitting: Development and application to geometry optimization in the ground and excited states

The Journal of Chemical Physics ◽

10.1063/5.0039258 ◽

2021 ◽

Vol 154 (7) ◽

pp. 074108

Author(s):

Thais R. Scott ◽

Meagan S. Oakley ◽

Matthew R. Hermes ◽

Andrew M. Sand ◽

Roland Lindh ◽

...

Keyword(s):

Density Functional Theory ◽

Excited States ◽

Density Functional ◽

Geometry Optimization ◽

Functional Theory ◽

Pair Density ◽

Density Fitting

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Ground- and excited-state characteristics in photovoltaic polymer N2200

RSC Advances ◽

10.1039/d1ra01474a ◽

2021 ◽

Author(s):

Guanzhao Wen ◽

Xianshao Zou ◽

Rong Hu ◽

Jun Peng ◽

Zhifeng Chen ◽

...

Keyword(s):

Density Functional Theory ◽

Excited State ◽

Steady State ◽

Excited States ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Time Dependent ◽

Functional Theory ◽

Time Resolved ◽

Dependent Density

Ground- and excited-states properties of N2200 have been studied by steady-state and time-resolved spectroscopies as well as time-dependent density functional theory calculations.

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