scholarly journals Polyelectrolyte chain at thermal equilibrium: A comparison between the density functional theory framework (DFT) and the molecular dynamic simulations (MD)

2021 ◽  
Author(s):  
Mike J. Edwards
Keyword(s):  
Density Functional Theory ◽  
Molecular Dynamic ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Molecular Dynamic Simulations ◽  
Dynamic Simulations ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Bjerrum Length ◽  
Theory Framework

ABSTRACTBy means of the density functional theory framework (DFT) as well as the molecular dynamic simulations (MD), a polyelectrolyte chain (PE) in the good solvent conditions at thermal equilibrium is studied. The strength of the electrostatic interactions is varied by the Bjerrum length of the solvent. It turns out that average extension of a PE scales with the degree of polymerization, very much similar to a neutral polymer chain in good solvent. Remarkably, the difference between a PE and a neutral chain appears to be solely in the correlations among monomers which are stored in the Virial coefficients. Interestingly, upon increasing the Bjerrum length of solvent, the chain shrinks. This outcome is confirmed by the DFT framework as well as the MD simulations.SIGNIFICANCEThe significance of this study is that it strongly criticizes the idea (already mentioned in T. Kreer, Soft Matter, 12, 3479 (2016)) that the PEs behave similar to a neutral ideal chain. This study could be useful in our understanding of biopolymers.

scholarly journals The role of water co-adsorption on the modification of ZnO nanowires using acetic acid

2014 ◽  
Vol 16 (18) ◽  
pp. 8509-8514 ◽  
Author(s):  
Adriel Domínguez ◽  
Svea grosse Holthaus ◽  
Susan Köppen ◽  
Thomas Frauenheim ◽  
Andreia Luisa da Rosa
Keyword(s):  
Density Functional Theory ◽  
Acetic Acid ◽  
Molecular Dynamic ◽  
Density Functional ◽  
Co Adsorption ◽  
Zno Nanowires ◽  
Molecular Dynamic Simulations ◽  
Dynamic Simulations ◽  
Functional Theory

Density functional theory (DFT) and Car–Parinello molecular dynamic simulations were employed to investigate the interaction of acetic acid with non-polar facets of ultra-thin ZnO nanowires.

scholarly journals Interpenetration between a polymer brush and a polymer star at thermal equilibrium: A theoretical approach

2018 ◽  
Author(s):  
Mike Edwards
Keyword(s):  
Density Functional Theory ◽  
Theoretical Approach ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Polymer Brush ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Theory Framework ◽  
Absorption Transitions ◽  
Standing Problem

By means of the density functional theory framework I tackle the long-standing problem of a polymer star interpenetrating with a polymer brush at thermal equilibrium. Remarkably, the star is repelled to the outside of the brush once it sucks into the brush. It turns out that there could be a highly fluctuating region at the brush edge. The highly fluctuating region would be responsible for discontinuous absorption transitions by brushes. However, up to an small interpenetration length, below which asphericity of the star is maintained, the star gets collapsed by sucking more and more into the brush.

scholarly journals Polyelectrolyte brush bilayer under shear at linear and nonlinear response regimes: A combination of the density functional theory framework and the scaling theory

2021 ◽  
Author(s):  
Mike John Edwards
Keyword(s):  
Density Functional Theory ◽  
Shear Rate ◽  
Friction Coefficient ◽  
Electrostatic Interactions ◽  
Density Functional ◽  
Hydrodynamic Interactions ◽  
Functional Theory ◽  
Global Restructuring ◽  
The Density Functional Theory ◽  
Theory Framework

The density functional theory framework and the scaling theory are employed to approach the problem of the Polyelectrolyte brush bilayer under shear. It turns out that, the system at shear rates larger than a critical shear rate undergo a global restructuring during which chains stretch in the shear direction. In the absence of the electrostatic interactions as well as the hydrodynamic interactions, this global restructuring causes a sublinear scaling of the shear stress with the shear rate which makes the shear thinning effect. Nevertheless, in the presence of the hydrodynamic interactions, not only there is no sublinear regime but also a weak superlinear regime which makes a weak shear thickening effect. In the presence of the electrostatic interactions, the stress tensor components change by their second Virial coefficients, however, their shear rate power law are untouched. Nonetheless, the kinetic friction coefficient is independent of the electrostatic interactions. This suggests that the lubrication is not very much different than the neutral bilayers and the electrostatic interactions do not change that. The results of this study offers that maybe nature uses another mechanism to reduce friction coefficient in synovial joint and other biological systems.

scholarly journals New Insights to Understand the CoMFA Analysis within the Density Functional Theory Framework

2021 ◽  
Vol 2 (11) ◽  
pp. 1067-1073
Author(s):  
Roya Momen ◽  
Alejandro Morales-Bayuelo
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Chemical Reactivity ◽  
3D Qsar ◽  
Quantum Similarity ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
The Density Functional Theory ◽  
Wide Range ◽  
Theory Framework

The Three-Dimensional Quantitative Structure-Activity Relationship (3D QSAR) models now have a wide range of applications; however, new methodologies are required due to the complexity in understanding their results. This research presents a generalized version of quantum similarity field and chemical reactivity descriptors within the density functional theory framework. By taking reference compounds, this generalized methodology can be used to understand the biological activity of a molecular set. In this sense, this methodology allows to study of the CoMFA in quantum similarity and chemical reactivity. It is feasible to investigate steric and electrostatic effects on local substitutions using this method. They were considering that how these methodologies could be used when the receptor is known or unknown.

Barium disilicide as a promising thin-film photovoltaic absorber: structural, electronic, and defect properties

2017 ◽  
Vol 5 (48) ◽  
pp. 25293-25302 ◽  
Author(s):  
Mukesh Kumar ◽  
Naoto Umezawa ◽  
Wei Zhou ◽  
Motoharu Imai
Keyword(s):  
Thin Film ◽  
Density Functional Theory ◽  
Solar Cells ◽  
Molecular Orbital ◽  
Density Functional ◽  
Thin Film Solar Cells ◽  
Functional Theory ◽  
Absorber Material ◽  
The Density Functional Theory ◽  
Theory Framework

We report on a barium disilicide (BaSi2) system as a potential absorber material for thin-film solar cells within the density functional theory framework by using advanced methods like GW and BSE and elucidate the first report on the molecular orbital diagram and defect physics in BaSi2.

scholarly journals Metallic and intra-band investigation of optical properties for Borophene nano-sheet: a DFT study

2019 ◽  
Vol 10 (1) ◽  
pp. 33-41
Author(s):  
T. Abasi ◽  
A. Boochani ◽  
S. R. Masharian
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Incident Light ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Semiconductor Behavior ◽  
Structure Density ◽  
Theory Framework

AbstractIn this paper, using the density functional theory framework with the FP-LAPW + lo method by GGA approximation, the electronic and optical properties such as band structure, density of states, dielectric function, energy loss function, absorption and reflection have been investigated for borophene nano-sheet. The optical properties of the borophene have been changed as the incident light direction whereas has the metallic and semiconductor behavior, in the borophene sheet and perpendicular light angles, respectively. Therefore, it can be said that the optical properties of this material are anisotropic.

Mechanical properties and variation in SOC going from La to Nd in intermetallic RIn3 and RSn3 (R = La, Ce, Pr, Nd)

RSC Advances ◽  
2015 ◽  
Vol 5 (49) ◽  
pp. 39416-39423 ◽  
Author(s):  
M. Shafiq ◽  
Iftikhar Ahmad ◽  
S. Jalali-Asadabadi
Keyword(s):  
Mechanical Properties ◽  
Density Functional Theory ◽  
Rare Earth ◽  
Density Functional ◽  
Plane Waves ◽  
Orbital Method ◽  
Full Potential ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Theory Framework

The cubic rare-earth intermetallics RIn3 and RSn3 (R = La, Ce, Pr, Nd) have been investigated using the full potential linearized augmented plane waves plus local orbital method in the density functional theory framework.

Sign in / Sign up

Export Citation Format

Share Document