scholarly journals Electrostatic energy of interaction between uniformly charged hemispherical surfaces

2022 ◽  
Vol 115 ◽  
pp. 103666
Author(s):  
Orion Ciftja
Keyword(s):  
Electrostatic Energy ◽  
Energy Of Interaction

Quantum-Chemical Investigations on the Structural Variability of Anion–π Interactions

2014 ◽  
Vol 69 (7) ◽  
pp. 339-348 ◽  
Author(s):  
Verena Moha ◽  
Michael Giese ◽  
Richard Moha ◽  
Markus Albrecht ◽  
Gerhard Raabe
Keyword(s):  
Gas Phase ◽  
Aromatic Ring ◽  
Energy Surface ◽  
Electrostatic Energy ◽  
Dispersion Energy ◽  
Substitution Pattern ◽  
Energy Of Interaction ◽  
Electron Withdrawing Group ◽  
Energy Surfaces ◽  
Structural Versatility

The structural versatility of anion-p interactions was investigated computationally. Employing quantum-chemically optimized structures of a series of C6H6-nFn/Br- complexes and the Coulomb law together with the London formula to calculate the electrostatic and the dispersion energy of the interaction between the anion and the π-system led to the result that up to the number of n = 2 due to a significantly repulsive electrostatic energy of interaction the dispersion energy is not sufficient to stabilize such structures in the gas phase where the anion is located above the plane defined by the aromatic ring. The energy surfaces resulting from the interaction of bromide anions with isolated arenes bearing varying numbers of fluorine atoms in different positions of the aromatic ring also show a pronounced dependency on the subsitution pattern of the aromatic system. Depending on the nature of the electron withdrawing group and its position, the energy surface can have a sharply defined energetically low minimum, in which the anion is ‘fixed’. Other substitution patterns result in very flat energy surfaces, and even a surface with more than two local minima within the scanned area was found. Thus, our study reveals the reason for the experimentally observed structural versatility depending on the substitution pattern in the solid state.

scholarly journals Modelling Colloidal Stability in Gold Nanoparticles Synthesis - A Review

2020 ◽  
pp. 59-69
Author(s):  
Babalola Faith U.
Keyword(s):  
Gold Nanoparticles ◽  
Brownian Motion ◽  
Colloidal Stability ◽  
Dlvo Theory ◽  
Electrostatic Energy ◽  
Aggregation Process ◽  
Colloidal Systems ◽  
Nanoparticles Synthesis ◽  
Electrostatic Effect ◽  
Energy Of Interaction

Nanoparticles are commonly synthesized in colloidal systems, a liquid with suspended macromolecules. By the Brownian motion, these particles can collide and aggregate, leading to larger particles. To stabilize the aggregation process, charges induced by ions cause repulsion among the particles. Through the works of researchers in the past, various models for describing particles aggregation and stabilization have been developed and modified. These models are based on the popular DLVO theory, named after Derjaguin, Landau, Verwey and Overbreek. In this work, evidence illustrating aggregation and stabilization in gold nanoparticles synthesis is reported. Thereafter, models for describing aggregation by the Brownian motion and stabilization by the electrostatic effect are reviewed. The electrostatic effect among the particles is mathematically expressed as the cumulative sum of the Van der Waal’s energy of interaction and the electrostatic energy of repulsion. As the resulting stabilization model is too complex to solve, past researchers reported a simplified stabilization submodel and employed it in describing gold nanoparticles synthesis. Unfortunately, as shown in this review, the submodel failed to describe the synthesis as the aggregation process never stopped, thus making a case for a new modelling approach.

scholarly journals Rationalising molecular crystal structures using Hirshfeld surfaces

2014 ◽  
Vol 70 (a1) ◽  
pp. C34-C34
Author(s):  
Mark Spackman
Keyword(s):  
Crystal Packing ◽  
Close Contact ◽  
Hirshfeld Surface ◽  
Electrostatic Energy ◽  
Quantum Mechanical ◽  
Hirshfeld Surfaces ◽  
Visual Approach ◽  
Energy Of Interaction ◽  
Molecular Wavefunctions ◽  
Patterns Of Interaction

Hirshfeld surface analysis [1] has very quickly become a routine tool for rationalising and visualising intermolecular interactions in crystals. The serendipitous discovery of an intriguing and novel way to identify the space `belonging' to a molecule in a crystal has led to the development of a suite of computational tools that facilitate a deeper understanding of how molecules pack in crystals and why it makes sense that a particular crystal packing occurs [2]. We have previously used the Hirshfeld surface as a vehicle for mapping inherent shape and curvature, surface-mediated distances between closest atoms, as well as quantum mechanical properties such as molecular orbital density, electron density and electrostatic potential. Combining visualisation tools like these with quantum mechanical wavefunctions – and hence properties derived from these wavefunctions – offers a powerful and unique opportunity to investigate intuitive concepts like `electrostatic complementarity' [3]. With this in mind we have been investigating ways to subdivide Hirshfeld surfaces into discrete patches that can be identified with specific pairs of molecules in close contact in crystals, and testing different expressions to quantify our ideas on electrostatic complementarity. Coupled with this appealing visual approach we also compute the electrostatic energy of interaction between the respective molecular wavefunctions. This combination of approaches within an easy to use software package will be powerful enough to not only routinely explore and visualise the patterns of interaction exhibited by molecules in crystals, but also provide meaningful energies of interaction between relevant pairs of molecules. In this way we can readily attach some real significance – energetics – to what are more usually classified as close contacts of various kinds.

Effect of energy filtering on micro-diffraction in the SEM

1994 ◽  
Vol 52 ◽  
pp. 604-605
Author(s):  
James F. Mancuso ◽  
Leo A. Fama ◽  
William B. Maxwell ◽  
Jerry L. Lehman ◽  
Hasso Weiland ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Ccd Camera ◽  
High Gain ◽  
Microchannel Plate ◽  
Electrostatic Energy ◽  
Energy Filtering ◽  
Electron Channelling ◽  
Low Energy Electrons ◽  
Low Sensitivity ◽  
Angular Field Of View

Micro-diffraction based crystallography is essential to the design and development of many classes of ‘crafted materials’. Although the scanning electron microscope can provide crystallographic information with high spatial resolution, its current utility is severely limited by the low sensitivity of existing diffraction techniques (ref: Dingley). Previously, Joy showed that energy filtering increased contrast and pattern visibility in electron channelling. This present paper discribes the effect of energy filtering on EBSP sensitivity and backscattered SEM imaging.The EBSP detector consisted of an electron energy filter, a microchannel plate detector, a phosphor screen, optical coupler, and a slow scan CCD camera. The electrostatic energy filter used in this experiment was constructed as a cone with 5 coaxial electrodes. The angular field-of-view of the filter was approximately 38°. The microchannel plate, which was the initial sensing component, had high gain and had 50% to 80% detection efficiency for the low energy electrons that passed through the retarding field filter.

ELECTROSTATIC ENERGY AND LATTICE VIBRATIONS IN THIN IONIC SLABS

1981 ◽  
Vol 42 (C6) ◽  
pp. C6-341-C6-343
Author(s):  
G. Kanellis ◽  
J. F. Morhange ◽  
M. Balkanski
Keyword(s):  
Electrostatic Energy ◽  
Lattice Vibrations

Physico-Chemical Explanation of Blood Cell Adhesion in Thrombus Formation

1976 ◽  
Vol 36 (02) ◽  
pp. 430-440 ◽  
Author(s):  
A Marmur ◽  
E Ruckenstein ◽  
S. R Rakower
Keyword(s):  
Blood Cells ◽  
Thrombus Formation ◽  
Experimental Information ◽  
Deposition Surface ◽  
Physico Chemical ◽  
Quantitative Results ◽  
Energy Of Interaction ◽  
Induced Aggregation ◽  
Adhesion Of Platelets ◽  
Hydrodynamic Factors

SummaryA model is suggested which assumes that the rate of deposition of cells is determined both by hydrodynamic factors and by Brownian motion over the potential barrier caused by London and double-layer forces in the immediate vicinity of the deposition surface. The height of the barrier in the potential energy of interaction between blood cells and various surfaces is analyzed in relation to the physical properties of the cells, surfaces, and solutions. Based on this analysis, the adhesion of platelets to injured blood vessel walls and to non-biologic materials, the lack of adhesion of red blood cells under the same conditions, the mechanism of ADP induced aggregation and the interaction with blood flow are explained. The qualitative predictions of the model are substantiated by available experimental information. Quantitative results are presented in terms of a time constant, which typifies a period of contact with a surface, during which appreciable deposition occurs.

Improvement of Power Generation in Low Acceleration for Electrostatic Energy Harvester by Using Bipolar Charging Method

2015 ◽  
Vol 135 (9) ◽  
pp. 372-373 ◽  
Author(s):  
Koji Sonoda ◽  
Keidai Minami ◽  
Naoki Miwatani ◽  
Kensuke Kanda ◽  
Takayuki Fujita ◽  
...  
Keyword(s):  
Power Generation ◽  
Energy Harvester ◽  
Electrostatic Energy

The Energy of the Electrostatic Field

2020 ◽  
Vol 67 (1) ◽  
pp. 35-41
Author(s):  
Igor’ P. Popov
Keyword(s):  
Electrostatic Field ◽  
Energy System ◽  
Electrostatic Energy ◽  
Research Purpose ◽  
Target System ◽  
Mathematical Form ◽  
Stored Energy ◽  
Energy Materials ◽  
Modeling And Analysis ◽  
Maximum Work

The work is actual due to the increased role of electrostatic energy in connection with the beginning of mass production of ionistors used in the power supply system of electric vehicles, and the need for the development of theoretical support. (Research purpose) The research purpose is in increasing the correctness of electrostatic calculations that exclude the possibility of obtaining unreliable results in the form of infinite electrostatic energy. (Materials and methods) Authors have used methods of mathematical modeling and analysis, studied the mathematical model as the equivalent of an object that reflects in mathematical form its most important properties, such as the laws that it obeys, and the relationships inherent in its constituent parts. (Results and discussion) Authors have studied the electrostatic field created by a system of two charges of the same name or different names. The article presents calculations for charges located in bodies that have the shape of balls. It was found that the results could be generalized to any form of charged objects. They gave three definitions: first, the total stored energy is the energy of the system or object, equal to the maximum work that the system or object can do if it is given such an opportunity. Second, the conditional realized stored energy is a part of the total stored energy of the system or object, equal to the work that the system or object can produce, limited by a condition that excludes the possibility of the system or object performing the maximum work that the system or object can hypothetically perform. The third is a conditional impossible reserved energy as a part of a complete stored energy system or an object that is equal to the work system or object can do and limited by the condition, which excludes the possibility of making a system or object maximum work that target system or object could hypothetically do. Five theorems were proved. (Conclusions) It was found that the main drawback of the actual potential energy formula is an infinitely large increase in energy at radius tending to 0. The obtained formulas for stored electrostatic energy are devoid of this drawback.

scholarly journals Molecular Dynamics Simulation on the Interaction between Palygorskite Coating and Linear Chain Alkane Base Lubricant

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 286
Author(s):  
Jin Zhang ◽  
Lv Yang ◽  
Yue Wang ◽  
Huaichao Wu ◽  
Jiabin Cai ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Structural Changes ◽  
Molecular Diffusion ◽  
Linear Chain ◽  
Interfacial Interaction ◽  
Dynamics Simulation ◽  
Electrostatic Energy ◽  
Experimental Development ◽  
Practical Applications ◽  
Self Diffusion

Molecular dynamics (MD) simulations were conducted to investigate the interactions between a palygorskite coating and linear chain alkanes (dodecane C12, tetradecane C14, hexadecane C16, and octadecane C18), representing base oils in this study. The simulation models were built by placing the alkane molecules on the surface of the palygorskite coating. These systems were annealed and geometrically optimized to obtain the corresponding stable configurations, followed by the analysis of the structural changes occurring during the MD process. The interfacial interaction energies, mean square displacements, and self-diffusion coefficients of the systems were evaluated to characterize the interactions between base lubricant molecules and palygorskite coating. It was found that the alkanes exhibited self-arrangement ability after equilibrium. The interfacial interaction was attractive, and the electrostatic energy was the main component of the binding energy. The chain length of the linear alkanes had a significant impact on the intensity of the interfacial interactions and the molecular diffusion behavior. Moreover, the C12 molecule exhibited higher self-diffusion coefficient values than C14, C16 and C18. Therefore, it could be the best candidate to form an orderliness and stable lubricant film on the surface of the palygorskite coating. The present work provides new insight into the optimization of the structure and composition of coatings and lubricants, which will guide the experimental development of these systems for practical applications.

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