Ab initio study of the (BH)2 dimer

1980 ◽  
Vol 45 (12) ◽  
pp. 3270-3282 ◽  
Author(s):  
Miroslav Urban ◽  
Soňa Hrivnáková ◽  
Pavel Hobza
Keyword(s):  
Perturbation Theory ◽  
Ab Initio ◽  
Interaction Energy ◽  
Multipole Expansion ◽  
Coulomb Energy ◽  
Interaction Energies ◽  
Ab Initio Study ◽  
Linear Arrangement ◽  
Total Interaction Energy ◽  
Total Interaction

The total interaction energy between two BH molecules was calculated as a sum of the SCF and correlation interaction energies. The latter was obtained either semiempirically or by the 2nd and 3rd order perturbation theory. It appeared to be the main contribution to the total interaction energy with some geometries. Important differences in the SCF interaction energy of different geometrical configurations of the dimer were explained by the utilization of higher terms of the Coulomb energy multipole expansion. Unexpectedly the geometry of highest stability does not correspond to the linear arrangement of the dimer but rather to the T-shaped structure.

Ion solvation by dipolar aprotic solvents. An ab initio study

1987 ◽  
Vol 52 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Petr Kyselka ◽  
Zdeněk Havlas ◽  
Ivo Sláma
Keyword(s):  
Ab Initio ◽  
Geometry Optimization ◽  
Molecular Structures ◽  
Dimethyl Sulphoxide ◽  
Ion Solvation ◽  
Interaction Energies ◽  
Ab Initio Study ◽  
Solvation Energies ◽  
Dipolar Aprotic Solvents ◽  
Complete Geometry Optimization

The paper deals with the solvation of Li+, Be2+, Na+, Mg2+, and Al3+ ions in dimethyl sulphoxide, dimethylformamide, acetonitrile, and water. The ab initio quantum chemical method was used to calculate the solvation energies, molecular structures, and charge distributions for the complexes water···ion, acetonitrile···ion, dimethyl sulphoxide···ion, and dimethylformamide···ion. The interaction energies were corrected for the superposition error. Complete geometry optimization was performed for the complex water···ion. Some generalizations are made on the basis of the results obtained.

Sodium Interaction with Disodium Terephthalate Molecule: an Ab Initio Study

MRS Advances ◽  
2016 ◽  
Vol 1 (53) ◽  
pp. 3579-3584 ◽  
Author(s):  
Mahasin Alam Sk ◽  
Sergei Manzhos
Keyword(s):  
Ab Initio ◽  
Interaction Energy ◽  
Terephthalic Acid ◽  
Disodium Salt ◽  
Ab Initio Study ◽  
Binding Mechanism ◽  
Carboxylate Groups ◽  
Organic Electrode ◽  
Occupied Orbital ◽  
Electron Occupation

ABSTRACTDisodium terephthalate (Na2TP), which is a disodium salt of terephthalic acid, is very promising organic electrode material for Na-ion batteries. We present an ab initio study of Na binding mechanism with Na2TP molecule. Specially, we provide the interaction energy of Na atom(s), effect of Na concentration on interaction energy, electronic properties of clean and Na attached Na2TP, and Na binding mechanism with Na2TP. We show that up to eight Na atoms can be attached to a single Na2TP molecule. The interaction energy of Na atoms varies from -0.79 to -0.66 eV with attachment of one to eight Na atoms. The adsorbed Na atom interacts with O atoms of carboxylate group and Na atoms of the salt molecule. The interaction between adsorbed Na and C atoms of the molecule is found to be not important for Na bindings. Attachment of a single Na atom generates a singly occupied orbital which becomes doubly occupied with attachment of second Na atoms. Attachment of more than two Na atoms leads to electron occupation of bonding orbitals formed between Na atoms and the carboxylate groups.

Zeta-Potential Investigation and Experimental Study of Nanoparticles Deposited on Rock Surface To Reduce Fines Migration

SPE Journal ◽  
2013 ◽  
Vol 18 (03) ◽  
pp. 534-544 ◽  
Author(s):  
M.. Ahmadi ◽  
A.. Habibi ◽  
P.. Pourafshary ◽  
S.. Ayatollahi
Keyword(s):  
Zeta Potential ◽  
Interaction Energy ◽  
Fine Particles ◽  
Rock Surface ◽  
Production Engineering ◽  
Release Process ◽  
Fines Migration ◽  
Total Interaction Energy ◽  
Total Interaction ◽  
Potential Test

Summary Fines migration is a noticeable problem in petroleum-production engineering. Plugging of throats in porous media occurs because of detachment of fine particles from sand surfaces. Thus, the study of interactions between fines and pore surfaces and the investigation of governing forces are important factors to consider when describing the mechanism of the fines-release process. The main types of these forces are electric double-layer repulsion (DLR) and London–van der Waals attraction (LVA). It may be possible to alter these forces with nanoparticles (NPs) as surface coatings. In comparison with repulsion forces, NPs increase the effect of attraction forces. In this paper, we present new experiments and simple modeling to observe such properties of NPs. For this purpose, the surfaces of pores were coated with different types of NPs: magnesium oxide (MgO), silicon dioxide (SiO2), and aluminum oxide (Al2O3). A zeta-potential test was used to examine changes in the potential of the pore surfaces. Total interaction energy was then mathematically calculated to compare different states. Total interaction energy is a fitting criterion that gives proper information about the effect of different NPs on surface properties. Consequently, total interaction plots are found to be suitable tools for selecting the best coating material. On the basis of experimental results, the magnitude of change in zeta potential for the MgO NP was 45 mV. Our model demonstrated that the magnitude of the electric DLR in comparison with the LVA of the probe and plate surface was considerably diminished when MgO NPs were used to coat the surface of the plate, which agrees completely with our experimental observation.

Ab Initio Study of Solvent Effects on Rate of 1,3-Dipolar Cycloadditions of Benzonitrile Oxide and Various Dipolarophiles

2003 ◽  
Vol 2003 (2) ◽  
pp. 91-95 ◽  
Author(s):  
E. Rajaeian ◽  
M. Monajjemi ◽  
M.R. Gholami
Keyword(s):  
Hydrogen Bonding ◽  
Oxygen Atom ◽  
Water Molecule ◽  
Ab Initio ◽  
Solvent Effects ◽  
Transition States ◽  
Molecular Orbital Calculations ◽  
Interaction Energies ◽  
Ab Initio Study ◽  
Dipolar Cycloadditions

Ab initio molecular orbital calculations have been used to investigate the structures and the transition states of 1,3-dipolar cycloadditions between benzonitrile oxide with ethylene, cyclopentene, acrylonitrile and tetracyanoethylene in heptane and water: calculations reveal enhanced hydrogen bonding of a water molecule to the transition states for the cycloaddition 1,3-dipolar of reaction of benzonitrile oxide with cyclopentene, the optimal interaction energies being 0.7 kcal/mol more favourable for hydrogen bonding to the oxygen atom in the transition states than for the reactants.

DISTRIBUTION OF POINT CHARGES ON A THIN CONDUCTING DISK

2000 ◽  
Vol 11 (05) ◽  
pp. 891-900 ◽  
Author(s):  
H. OYMAK ◽  
Ş. ERKOÇ
Keyword(s):  
Interaction Energy ◽  
Coulomb Potential ◽  
Minimum Energy ◽  
Total Interaction Energy ◽  
Thin Conducting ◽  
Total Interaction ◽  
Energy Configurations

We investigate the minimum energy configuration of N equal point charges interacting via the Coulomb potential 1/r, and placed on an infinitely thin conducting disk. By minimizing total interaction energy, we obtain numerically the minimum energy configurations from which the rules for the distribution of charges on the disk are obtained.

The Mechanism of Activated Sludge Flocculation under Al3+ Dosin

2014 ◽  
Vol 675-677 ◽  
pp. 106-110
Author(s):  
Wan Lin Zheng ◽  
A Sheng Cao ◽  
Yue Wen ◽  
Hai Rong Chen ◽  
Qi Zhou
Keyword(s):  
Zeta Potential ◽  
Activated Sludge ◽  
Interaction Energy ◽  
Equivalent Dose ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Total Interaction Energy ◽  
Total Interaction ◽  
Continuous Dosing ◽  
Opposite Tendency

The mechanism governing activated sludge flocculation under Al3+ dosing was studied in this paper. Activated sludge was cultivated in sequencing batch reactors (SBR) at 22°C. Batch dosages of Al3+ were 0.00, 0.125, 0.5, 1 and 1.5meq/L respectively, and continuous dosage was 0.1meq/L. As batch dosage increased, the total interaction energy, zeta potential and turbidity tended to decline, which suggested that batch dosing promoted sludge flocculation. Under the equivalent dose, the zeta potential of continuous dosing was higher, while the LB-EPS content showed the opposite tendency and turbidity reduction was similar. Both batch and continuous dosing promoted flocculation performance: in terms of interaction energy, batch dosing was more effective; while in terms of EPS, it was on the contrary.

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