Constrained dipole moment density functional theory for charge distributions in force fields for the study of molecular fluids

2020 ◽  
Vol 152 (12) ◽  
pp. 124116 ◽  
Author(s):  
Javier Carmona-Espíndola ◽  
Edgar Núñez-Rojas ◽  
Valeria García-Melgarejo ◽  
José L. Gázquez ◽  
José Alejandre
Keyword(s):  
Density Functional Theory ◽  
Dipole Moment ◽  
Density Functional ◽  
Force Fields ◽  
Functional Theory ◽  
Molecular Fluids ◽  
Charge Distributions

Structural polymorphism of pyrazinium hydrogen sulfate: extending chemistry of the pyrazinium salts with small anions

2010 ◽  
Vol 66 (4) ◽  
pp. 451-457 ◽  
Author(s):  
Armand Budzianowski ◽  
Mariana Derzsi ◽  
Piotr J. Leszczyński ◽  
Michał K. Cyrański ◽  
Wojciech Grochala
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Dipole Moment ◽  
Hydrogen Bonds ◽  
Dft Calculations ◽  
Density Functional ◽  
Hydrogen Sulfate ◽  
Structural Polymorphism ◽  
Functional Theory ◽  
First Time

Two polymorphs (α, β) of pyrazinium hydrogen sulfate (pyzH+HSO_4^-, abbreviated as PHS) with distinctly different hydrogen-bond types and topologies but close electronic energies have been synthesized and characterized for the first time. The α-polymorph (P212121) forms distinct blocks in which the pyzH+ and HSO_4^- ions are interconnected through a network of NH...O and OH...O hydrogen bonds. The β-form (P\bar 1) consists of infinite chains of alternating pyzH+ and HSO_4^- ions connected by NH...O and OH...N hydrogen bonds. Density functional theory (DFT) calculations indicate the possible existence of a hypothetical polar P1 form of the β-polymorph with an unusually high dipole moment.

Density functional theory and empirical derived force fields for the delocalized polaron form of polyaniline

2005 ◽  
Vol 61 (7) ◽  
pp. 1419-1429 ◽  
Author(s):  
Z. Cherrak ◽  
P. Lagant ◽  
N. Benharrats ◽  
A. Semmoud ◽  
F. Hamdache ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Force Fields ◽  
Functional Theory

Unusual effects of solvent polarity on capacitance for organic electrolytes in a nanoporous electrode

Nanoscale ◽  
2014 ◽  
Vol 6 (10) ◽  
pp. 5545-5550 ◽  
Author(s):  
De-en Jiang ◽  
Jianzhong Wu
Keyword(s):  
Density Functional Theory ◽  
Dipole Moment ◽  
Density Functional ◽  
Solvent Polarity ◽  
Density Functional Theory Calculations ◽  
Organic Electrolyte ◽  
Functional Theory ◽  
Organic Electrolytes

Classical density functional theory calculations suggest that there is an optimal dipole moment for the solvent in an organic electrolyte supercapacitor.

Can Kohn–Sham density functional theory predict accurate charge distributions for both single-reference and multi-reference molecules?

2017 ◽  
Vol 19 (20) ◽  
pp. 12898-12912 ◽  
Author(s):  
Pragya Verma ◽  
Donald G. Truhlar
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functionals ◽  
Functional Theory ◽  
Charge Distributions

This work investigates the performances of a variety of density functionals for their ability to accurately predict charge distributions of a range of single- and multi-reference molecules.

scholarly journals Dipole Moment Calculations Using Multiconfiguration Pair-Density Functional Theory and Hybrid Multiconfiguration Pair-Density Functional Theory

2021 ◽  
Author(s):  
Aleksandr Lykhin ◽  
Donald Truhlar ◽  
Laura Gagliardi
Keyword(s):  
Density Functional Theory ◽  
Dipole Moment ◽  
Density Functional ◽  
Dipole Moments ◽  
Computational Cost ◽  
Strongly Correlated ◽  
Functional Theory ◽  
Active Space ◽  
Pair Density ◽  
Reasonable Behavior

The dipole moment is the molecular property that most directly indicates molecular polarity. The accuracy of computed dipole moments depends strongly on the quality of the calculated electron density, and the breakdown of single-reference methods for strongly correlated systems can lead to poor predictions of the dipole moments in those cases. Here, we derive the analytical expression for obtaining the electric dipole moment by multiconfiguration pair density functional theory (MC-PDFT), and we assess the accuracy of MC-PDFT for predicting dipole moments at equilibrium and nonequilibrium geometries. We show that MC-PDFT dipole moment curves have reasonable behavior even for stretched geometries, and they significantly improve upon the CASSCF results by capturing more electron correlation. The analysis of a dataset consisting of 18 first-row transition metal diatomics and 6 main-group polyatomic molecules with multireference character suggests that MC-PDFT and its hybrid extension (HMC-PDFT) perform comparably to CASPT2 and MRCISD+Q methods and have a mean unsigned deviation of 0.2–0.3 D with respect to the best available dipole moment reference values. We explored the dependence of the predicted dipole moments upon the choice of the on-top density functional and active space, and we recommend the tPBE and hybrid tPBE0 on-top choices for the functionals combined with the moderate correlated participating orbital scheme for selecting the active space. With these choices, the mean unsigned deviations (in debyes) of the calculated equilibrium dipole moments from the best estimates are 0.77 for CASSCF, 0.29 for MC-PDFT, 0.24 for HMC-PDFT, 0.28 for CASPT2, and 0.25 for MRCISD+Q. These results are encouraging because the computational cost of MC-PDFT or HMC-PDFT is largely reduced compared to the CASPT2 and MRCISD+Q methods.

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