scholarly journals A Facile Strategy to Prepare Small Water Clusters via Interacting with Functional Molecules

2021 ◽  
Vol 22 (15) ◽  
pp. 8250
Author(s):  
Shanmeiyu Zhang ◽  
Yanyan Zhang ◽  
Chongchong Wu ◽  
Hui Yang ◽  
Qiqi Zhang ◽  
...  
Keyword(s):  
Density Functional ◽  
Md Simulation ◽  
Water Clusters ◽  
Sodium Dodecyl ◽  
Water System ◽  
Functional Theory ◽  
Small Water ◽  
Research Fields ◽  
Simulation Calculation ◽  
Oilfield Development

Although small water clusters (SWCs) are important in many research fields, efficient methods of preparing SWCs are still rarely reported, which is mainly due to the lack of related materials and understanding of the molecular interaction mechanisms. In this study, a series of functional molecules were added in water to obtain small water cluster systems. The decreasing rate of the half-peak width in a sodium dodecyl sulfate (SDS)–water system reaches ≈20% at 0.05 mM from 17O nuclear magnetic resonance (NMR) results. Based on density functional theory (DFT) and molecular dynamics (MD) simulation calculation, it can be concluded that functional molecules with stronger negative electrostatic potential (ESP) and higher hydrophilicity have a stronger ability to destroy big water clusters. Notably, the concentrations of our selected molecule systems are one to two magnitudes lower than that of previous reports. This study provides a promising way to optimize aqueous systems in various fields such as oilfield development, protein stability, and metal anti-corrosion.

Structures of small water clusters using gradient-corrected density functional theory

1993 ◽  
Vol 207 (2-3) ◽  
pp. 208-213 ◽  
Author(s):  
K. Laasonen ◽  
M. Parrinello ◽  
R. Car ◽  
Changyol Lee ◽  
David Vanderbilt
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Water Clusters ◽  
Functional Theory ◽  
Small Water

Reciprocal Polarizable Embedding with a Transferable H2O Potential Function II: Application to (H2O)n Clusters & Liquid Water

2019 ◽  
Author(s):  
Asmus Ougaard Dohn ◽  
Elvar Jónsson ◽  
Hannes Jonsson
Keyword(s):  
Density Functional Theory ◽  
Liquid Water ◽  
Density Functional ◽  
Water Clusters ◽  
Theory Model ◽  
Coupling Scheme ◽  
Functional Theory ◽  
Total Polarization ◽  
Electrostatic Embedding ◽  
Polarizable Embedding

The manuscript analyzes the accuracy of our recently developed reciprocal polarizable embedding scheme, where a density functional theory model of the QM region is coupled to a dipole- and quadrupole polarizable water potential of the MM region. We present calculations of water clusters and liquid water where we analyze the energy, atomic forces and total polarization to demonstrate that artifacts in energy and polarization introduced by the QM/MM coupling are small and well-behaved. Furthermore, our methodology improves the consistency of the structure of optimized water hexamer geometries when compared to results obtained with models that neglect polarization. Additionally, the manuscript provides evidence that our coupling scheme eliminates artifacts in the structure of liquid water obtained with simpler electrostatic embedding models.

scholarly journals Evolution of Dirac Cone in Disclinated Graphene

2018 ◽  
Vol 57 (2) ◽  
pp. 137-142 ◽  
Author(s):  
M.A. Rozhkov ◽  
A.L. Kolesnikova ◽  
I. Hussainova ◽  
M.A. Kaliteevskii ◽  
T.S. Orlova ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Band Structure ◽  
Density Functional ◽  
Md Simulation ◽  
Dirac Cone ◽  
Electronic Band ◽  
Functional Theory ◽  
Periodic Distribution ◽  
Electronic Band Structures

Abstract Graphene crystals, containing arrays of disclination defects, are modeled and their energies are calculated using molecular dynamics (MD) simulation technique. Two cases are analyzed in details: (i) pseudo-graphenes, which contain the alternating sign disclination ensembles and (ii) graphene with periodic distribution of disclination quadrupoles. Electronic band structures of disclinated graphene crystals are calculated in the framework of density functional theory (DFT) approach. The evolution of the Dirac cone and magnitude of band gap in the band structure reveal a dependence on the density of disclination quadrupoles and alternating sign disclinations. The electronic properties of graphene with disclination ensembles are discussed.

Computational Study of Optical Properties of Cellulose Triacetate Film

2013 ◽  
Vol 1524 ◽  
Author(s):  
Daichi Hayakawa ◽  
Kazuyoshi Ueda
Keyword(s):  
Polymer Film ◽  
Density Functional ◽  
Md Simulation ◽  
Computational Study ◽  
Monomer Unit ◽  
Cellulose Triacetate ◽  
Functional Theory ◽  
Torsion Angles ◽  
Conformational Freedom ◽  
Intrinsic Birefringence

ABSTRACTThe birefringence of a cellulose triacetate (CTA) polymer film was evaluated based on density functional theory and molecular dynamics (MD) simulation. The polarizability of the monomer unit of CTA was initially calculated to determine the intrinsic properties of the birefringence of CTA. The most important conformational freedom of the CTA monomer unit is derived from the C-6 acetyl methyl groups. This exocyclic group is known to have three low energy conformers referred to as gg, gt, and tg according to the rotation of the different torsion angles. Because the polarizability can be viewed as dependent on the conformation of CTA, the polarizability of these three conformers was evaluated. The results demonstrated that negative intrinsic birefringence was associated with the CTA repeating units having gg or gt structures, whereas the monomer units with tg structures were characterized by positive intrinsic birefringence. A model of the polymer film was constructed based on MD simulation and the birefringence of the model was evaluated using the calculated monomer birefringence values. The birefringence of the CTA film was found to be negative because most of the CTA repeating units adopt the gg conformation in the film. The negative value of the simulated birefringence is in good agreement with the result obtained by the experiment.

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