scholarly journals Water on graphene: Hydrophobicity and dipole moment using density functional theory

2009 ◽  
Vol 79 (23) ◽  
Author(s):  
O. Leenaerts ◽  
B. Partoens ◽  
F. M. Peeters
Keyword(s):  
Density Functional Theory ◽  
Dipole Moment ◽  
Density Functional ◽  
Functional Theory

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.

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.

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.

scholarly journals Investigation of the Effects of Solvents on the Structural, Electronic and Thermodynamic Properties of Rosiglitazone Based on Density Functional Theory

2019 ◽  
pp. 1-18
Author(s):  
R. A. Ismail ◽  
A. B. Suleiman ◽  
A. S. Gidado ◽  
A. Lawan ◽  
A. Musa
Keyword(s):  
Density Functional Theory ◽  
Dipole Moment ◽  
Thermodynamic Properties ◽  
Gas Phase ◽  
Density Functional ◽  
Dielectric Constants ◽  
Basis Sets ◽  
Lumo Energy ◽  
Functional Theory ◽  
Homo Lumo

Rosiglitazone ( C18H19N3O3S ) is an anti-diabetic drug that reduces insulin resistance in patients with type 2 diabetes. The parameters (bond lengths and bond angles), HOMO, LUMO, HOMO-LUMO energy gap, dipole moment, thermodynamic properties, total energy and vibrational frequencies and intensities of the Rosiglitazone molecule in gas phase and in solvents (Water, Ethanol, DMSO and Acetonitrile) were calculated based on Density Functional Theory (DFT) using standard basis sets: B3LYP/6-31G(d,p), B3LYP/6-31+G(d,p) and B3LYP/6-31++G(d,p). Windows version of Gaussian 09 was used for all the calculations. From the results obtained, the solvents have little influence on the optimized parameters of the molecule. The highest HOMO value of -5.433 eV was found in gas phase showing that the molecule will best donate electron in the gas phase, followed by ethanol in comparison with other solvents. The values of the HOMO were observed to increase with the decrease in dielectric constants of the solvents across all the basis sets used. The lowest LUMO energy of -1.448 eV was found to be in ethanol which shows that the molecule will best accept electron in ethanol compared to the gas phase and other solvents. The largest HOMO-LUMO gap of 4.285 eV was found in water which shows its higher kinetic stability and less chemical reactivity compared to other solvents and in the gas phase. The chemical softness of the molecule was found to decrease as the dielectric constants of the solvents increased namely from ethanol to water. The chemical hardness was found to slightly increase with the increase in dielectric constants of the solvents. The highest value of the dipole moment of 4.6874 D was found in water indicating that the molecule will have the strongest intermolecular interactions in water compared to other solvents and in the gas phase. The total energy increased as the dielectric constants of the solvents decreased from water to ethanol. The vibrational frequencies and intensities increased as the dielectric constants of the solvents increased from ethanol to water. The results confirmed the effects of solvents on the structural, electronic and thermodynamic properties of the studied molecule and will be useful in the design and development of rosiglitazone as an anti-diabetic drug.

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

Fluorescent styryl chromophores with rigid (pyrazole) donor and rigid (benzothiophenedioxide) acceptor – complete density functional theory (DFT), TDDFT and nonlinear optical study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sulochana Bhalekar ◽  
Archana Bhagwat ◽  
Nagaiyan Sekar
Keyword(s):  
Density Functional Theory ◽  
Dipole Moment ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Absolute Error ◽  
Basis Sets ◽  
Chemical Hardness ◽  
Styryl Dyes ◽  
Functional Theory ◽  
Hybrid Functionals

Abstract Density functional theory (DFT) and time-dependent DFT computations were employed to examine linear and nonlinear optical (NLO) characteristics of (E)-4-((1,1-dioxido-3-oxobenzo[b]thiophen-2(3H)-ylidene) ethyl)-1-phenyl-1H-pyrazol-5(4H)-one derived styryl dyes. NLO properties were computed using the two different global hybrid functionals B3LYP, BHandHLYP and three range separated hybrid functionals CAM B3LYP, wB97, wB97X and wB97XD with the basis sets 6–311++G(d,p), cc-pVDZ and cc-pVTZ. The compounds shows higher values of dipole moment around 8–9 Debye than the other compounds. They show higher values of α 0, ß 0 and γ 0 values. The values of γ 0 are around 204–544 × 10−36 e.s.u. with the method, B3LYP/6–311++G(d, p). We have calculated the mean absolute error (MAE) for dipole moment, α 0, ß 0 and γ 0 values. It is observed that MAE is less (0.89) for wB97/6–311++G(d,p) which indicates that wB97 is the most suited functional for all three compounds. Chemical stability and reactivity of these dyes were studied using electrophilicity index and chemical hardness and hyperhardness.

scholarly journals Substituent Effects on the Solubility and Electronic Properties of the Cyanine Dye Cy5: Density Functional and Time-Dependent Density Functional Theory Calculations

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 524
Author(s):  
Austin Biaggne ◽  
William B. Knowlton ◽  
Bernard Yurke ◽  
Jeunghoon Lee ◽  
Lan Li
Keyword(s):  
Density Functional Theory ◽  
Dipole Moment ◽  
Density Functional ◽  
Dipole Moments ◽  
Time Dependent ◽  
Cyanine Dye ◽  
Transition Dipole ◽  
Functional Theory ◽  
Solvation Energies ◽  
Transition Dipole Moments

The aggregation ability and exciton dynamics of dyes are largely affected by properties of the dye monomers. To facilitate aggregation and improve excitonic function, dyes can be engineered with substituents to exhibit optimal key properties, such as hydrophobicity, static dipole moment differences, and transition dipole moments. To determine how electron donating (D) and electron withdrawing (W) substituents impact the solvation, static dipole moments, and transition dipole moments of the pentamethine indocyanine dye Cy5, density functional theory (DFT) and time-dependent (TD-) DFT calculations were performed. The inclusion of substituents had large effects on the solvation energy of Cy5, with pairs of withdrawing substituents (W-W pairs) exhibiting the most negative solvation energies, suggesting dyes with W-W pairs are more soluble than others. With respect to pristine Cy5, the transition dipole moment was relatively unaffected upon substitution while numerous W-W pairs and pairs of donating and withdrawing substituents (D-W pairs) enhanced the static dipole difference. The increase in static dipole difference was correlated with an increase in the magnitude of the sum of the Hammett constants of the substituents on the dye. The results of this study provide insight into how specific substituents affect Cy5 monomers and which pairs can be used to engineer dyes with desired properties.

Sign in / Sign up

Export Citation Format

Share Document