Density functional theory augmented with an empirical dispersion term. Interaction energies and geometries of 80 noncovalent complexes compared withab initioquantum mechanics calculations

2007 ◽  
Vol 28 (2) ◽  
pp. 555-569 ◽  
Author(s):  
Petr Jurečka ◽  
Jiří Černý ◽  
Pavel Hobza ◽  
Dennis R. Salahub
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Interaction Energies ◽  
Noncovalent Complexes ◽  
Functional Theory ◽  
Dispersion Term

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>

Influence of the adsorption of toxic agents on the optical and electronic properties of B12N12 fullerene in the presence and absence of an external electric field

2020 ◽  
Vol 44 (34) ◽  
pp. 14513-14528
Author(s):  
Alireza Soltani ◽  
Mohammad Ramezanitaghartapeh ◽  
Masoud Bezi Javan ◽  
Mohammad T. Baei ◽  
Andrew Ng Kay Lup ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electric Field ◽  
Dft Calculations ◽  
Electronic Properties ◽  
External Electric Field ◽  
Density Functional ◽  
Interaction Energies ◽  
Functional Theory ◽  
Toxic Agents ◽  
Optical And Electronic Properties

The interaction energies and optoelectronic properties of sarin (SF) and chlorosarin (SC) on the B12N12 with and without the presence of an electric field have been studied using density functional theory (DFT) calculations.

A theoretical study of weak interactions in phenylenediamine homodimer clusters

2016 ◽  
Vol 18 (42) ◽  
pp. 29249-29257 ◽  
Author(s):  
Chengqian Yuan ◽  
Haiming Wu ◽  
Meiye Jia ◽  
Peifeng Su ◽  
Zhixun Luo ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Intermolecular Interactions ◽  
Density Functional ◽  
Theoretical Study ◽  
Natural Bond Orbital ◽  
Weak Interactions ◽  
Interaction Energies ◽  
Functional Theory ◽  
Weak Intermolecular Interactions

Utilizing dispersion-corrected density functional theory (DFT) calculations, we demonstrate the weak intermolecular interactions of phenylenediamine dimer (pdd) clusters, emphasizing the local lowest energy structures and decomposition of interaction energies by natural bond orbital (NBO) and atoms in molecule (AIM) analyses.

scholarly journals Electronic And Nonlinear Optical Features of Inorganic Ga12N12 Nanocage Decorated With Alkali Metals (Li, Na and K)

2021 ◽  
Author(s):  
Azadeh Jamshidi ◽  
Zeinab Biglari
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Alkali Metals ◽  
Nonlinear Optical ◽  
Interaction Energies ◽  
First Hyperpolarizability ◽  
Negative Interaction ◽  
Functional Theory ◽  
Nlo Properties ◽  
Homo Lumo

Abstract The effect of alkali metals (Li, Na and K) interaction on the nonlinear optical response (NLO) of Ga12N12 nanocage has been performed using density functional theory (DFT) calculations. The results show that the exo-M@Ga12N12 structures are energetically favorable with negative interaction energies in the range of ‒1.50 to ‒2.28 eV. The electronic properties of decorated structures are strongly sensitive to interaction with the alkali metals. The HOMO-LUMO gap of Ga12N12 is reduced by about 70% due to the decoration with alkali metals. It is obtained that the adsorption of alkali metals over the tetragonal ring of Ga12N12 nanocage remarkably enhances the first hyperpolarizability up to 6.5×104 au. The results display that decorating Ga12N12 nanocage with alkali metals can be introduced it as a novel inorganic nanomaterial with significant NLO properties.

scholarly journals Theoretical Evaluation on The Interaction Between Triglycerides and Methylxanthines Using Density Functional Theory B3LYP/6-31G(d,p) and Molecular Electrostatic Potential

2020 ◽  
Vol 33 (1) ◽  
pp. 171-178
Author(s):  
N.F.M. Azmi ◽  
R. Ali ◽  
A.A. Azmi ◽  
M.Z.H. Rozaini ◽  
K.H.K. Bulat ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Electrostatic Potential ◽  
Density Functional ◽  
Molecular Electrostatic Potential ◽  
Basis Set ◽  
Individual Species ◽  
Interaction Energies ◽  
Binding Interaction ◽  
Functional Theory

The binding, interaction and distortion energies between the main triglycerides, palmitic-oleic-stearic (POS) in cocoa butter versus palmitic-oleic-palmitic (POP) in refined, bleached and deodorized (RBD) palm oil with cocoa′s methylxanthines (caffeine, theobromine, and theophylline) during the production of chocolate were theoretically studied and reported. The quantum mechanical software package of Gaussian09 at the theoretical level of density functional theory B3LYP/6-31G(d,p) was employed for all calculations, optimization, and basis set superposition errors (BSSE). Geometry optimizations were carried out to the minimum potential energy of individual species and binary complexes formed between the triglycerides, methylxanthines and polyphenols. The interaction energies for the optimized complexes were then corrected for the BSSE using the counterpoise method of Boys and Bernardi. The results revealed that the binding energy and interaction energy between methylxanthine components in cocoa powder with triglycerides were almost of the same magnitude (13.6-14.5 and 3.4-3.7 kJ/mol, respectively), except for the binary complex of POS-caffeine (25.1 and 10.7 kJ/mol, respectively). Based on the molecular geometry results, the hydrogen bond length and angle correlated well with the interaction energies. Meanwhile, the POS-caffeine complex with two higher and almost linear bond angles showed higher binding and interaction energies as compared to the other methylxanthines. Therefore, a donor-acceptor analysis showed that the hydrogen bond strength was proven using the molecular electrostatic potential (MEP), which resulted in parallel outcomes. The research results were believed to be one of the factors that contributed to the rheological behaviour and sensory perception of cocoa products, especially chocolate.

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