A theoretical study of weak interactions in phenylenediamine homodimer clusters

The interaction energies and optoelectronic properties of sarin (SF) and chlorosarin (SC) on the B12N12 with and without the presence of an electric field have been studied using density functional theory (DFT) calculations.

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Simulating Surfactant-Iron Oxide Interfaces: From Density Functional Theory to Molecular Dynamics

10.26434/chemrxiv.8325356 ◽

2019 ◽

Author(s):

Carlos Ayestaran Latorre ◽

James Ewen ◽

Chiara Gattinoni ◽

Daniele Dini

Keyword(s):

Molecular Dynamics ◽

Density Functional Theory ◽

Iron Oxide ◽

Dft Calculations ◽

Density Functional ◽

Md Simulations ◽

Oxide Surfaces ◽

Interaction Energies ◽

Functional Theory ◽

Oxide Interfaces

<div>Understanding the behaviour of surfactant molecules on iron oxide surfaces is important for many industrial applications. Molecular dynamics (MD) simulations of such systems have been limited by the absence of a force-feild (FF) which accurately describes the molecule-surface interactions. In this study, interaction energies from density functional theory (DFT) + U calculations with a van der Waals functional are used to parameterize a classical FF for MD simulations of amide surfactants on iron oxide surfaces. The Original FF, which was derived using mixing rules and surface Lennard-Jones (LJ) parameters developed for nonpolar molecules, were shown to signi cantly underestimate the adsorption energy and overestimate the equilibrium adsorption distance compared to DFT. Conversely, the Optimized FF showed excellent agreement with the interaction energies obtained from DFT calculations for a wide range of surface coverages and molecular conformations near to and adsorbed on a-Fe2O3(0001). This was facilitated through the use of a Morse potential for strong chemisorption interactions, modi fied LJ parameters for weaker physisorption interactions, and adjusted partial charges for the electrostatic interactions. The Original FF and Optimized FF were compared in classical nonequilibrium molecular dynamics (NEMD) simulations of amide molecules con fined between iron oxide surfaces. When the Optimized FF was employed, the amide molecules were pulled closer to the surface and the orientation of the headgroups was more similar to that observed in the DFT calculations compared to the Original FF. The Optimized FF proposed here facilitates classical MD simulations of amide-iron oxide interfaces in which the interactions are representative of accurate DFT calculations.</div>

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Theoretical study on the mechanism of iridium-catalyzed γ-functionalization of primary alkyl C–H bonds

Canadian Journal of Chemistry ◽

10.1139/cjc-2016-0287 ◽

2016 ◽

Vol 94 (12) ◽

pp. 1028-1037 ◽

Cited By ~ 4

Author(s):

Zhe Li ◽

Miaoren Xia ◽

Russell J. Boyd

Keyword(s):

Density Functional Theory ◽

Dft Calculations ◽

Experimental Observation ◽

Density Functional ◽

Theoretical Study ◽

Reductive Elimination ◽

Catalytic Cycle ◽

Catalyst Precursor ◽

Functional Theory ◽

Initial Formation

The mechanism of the iridium-catalyzed functionalization of a primary C–H bond at the γ position of an alcohol 5 is investigated by density functional theory (DFT) calculations. A new IrIII–IrV mechanism is found to be more feasible than the previously reported IrI–IrIII mechanism. 10 In the IrIII–IrV mechanism, the reaction begins with the initial formation of (Me4phen)IrIII(H)[Si(OR)Et2]2 from the catalyst precursor, [Ir(cod)OMe]2 (cod = 1,5-cyclooctadiene). The catalytic cycle includes five steps: (1) the insertion of norbornene into the Ir–H bond to produce (Me4phen)IrIII(norbornyl)[Si(OR)Et2]2 (R = –CH(C2H5)C3H7); (2) the Si–H oxidative addition of HSi(OR)Et2 to form (Me4phen)IrVH(norbornyl)[Si(OR)Et2]3; (3) the reductive elimination of norbornane to furnish (Me4phen)IrIII[Si(OR)Et2]3; (4) the intramolecular C–H activation of the primary C–H bond at the γ position; and (5) the Si–C reductive elimination to produce the final product and regenerate the catalyst. The highest barrier in the IrIII–IrV mechanism is 7.3 kcal/mol lower than that of the IrI–IrIII mechanism. In addition, the regioselectivity of the C–H activation predicted by this new IrIII–IrV mechanism is consistent with experimental observation.

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Structure-activity relationships in the production of olefins from alcohols and ethers: a first-principles theoretical study

Catalysis Science & Technology ◽

10.1039/c5cy00925a ◽

2015 ◽

Vol 5 (9) ◽

pp. 4547-4555 ◽

Cited By ~ 14

Author(s):

Pavlo Kostetskyy ◽

Giannis Mpourmpakis

Keyword(s):

Density Functional Theory ◽

Dft Calculations ◽

Lewis Acid ◽

First Principles ◽

Density Functional ◽

Theoretical Study ◽

Functional Theory ◽

Structure Activity Relationships ◽

Structure Activity

Olefin formation pathways on Lewis acid (LA) sites of Al2O3, Ga2O3 and In2O3 and gallium- and indium-doped alumina were investigated using Density Functional Theory (DFT) calculations.

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Distribution of dopant ions around poly(3,4-ethylenedioxythiophene) chains: a theoretical study

Physical Chemistry Chemical Physics ◽

10.1039/c7cp00857k ◽

2017 ◽

Vol 19 (15) ◽

pp. 9889-9899 ◽

Cited By ~ 3

Author(s):

Jordi Casanovas ◽

David Zanuy ◽

Carlos Alemán

Keyword(s):

Density Functional Theory ◽

Boundary Conditions ◽

Dft Calculations ◽

Density Functional ◽

Periodic Boundary ◽

Theoretical Study ◽

Periodic Boundary Conditions ◽

Polymer Chains ◽

Functional Theory

The effect of counterions and multiple polymer chains on the properties and structure of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with ClO4− has been examined using density functional theory (DFT) calculations with periodic boundary conditions (PBCs).

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Simulating Surfactant-Iron Oxide Interfaces: From Density Functional Theory to Molecular Dynamics

10.26434/chemrxiv.8325356.v1 ◽

2019 ◽

Author(s):

Carlos Ayestaran Latorre ◽

James Ewen ◽

Chiara Gattinoni ◽

Daniele Dini

Keyword(s):

Molecular Dynamics ◽

Density Functional Theory ◽

Iron Oxide ◽

Dft Calculations ◽

Density Functional ◽

Md Simulations ◽

Oxide Surfaces ◽

Interaction Energies ◽

Functional Theory ◽

Oxide Interfaces

<div>Understanding the behaviour of surfactant molecules on iron oxide surfaces is important for many industrial applications. Molecular dynamics (MD) simulations of such systems have been limited by the absence of a force-feild (FF) which accurately describes the molecule-surface interactions. In this study, interaction energies from density functional theory (DFT) + U calculations with a van der Waals functional are used to parameterize a classical FF for MD simulations of amide surfactants on iron oxide surfaces. The Original FF, which was derived using mixing rules and surface Lennard-Jones (LJ) parameters developed for nonpolar molecules, were shown to signi cantly underestimate the adsorption energy and overestimate the equilibrium adsorption distance compared to DFT. Conversely, the Optimized FF showed excellent agreement with the interaction energies obtained from DFT calculations for a wide range of surface coverages and molecular conformations near to and adsorbed on a-Fe2O3(0001). This was facilitated through the use of a Morse potential for strong chemisorption interactions, modi fied LJ parameters for weaker physisorption interactions, and adjusted partial charges for the electrostatic interactions. The Original FF and Optimized FF were compared in classical nonequilibrium molecular dynamics (NEMD) simulations of amide molecules con fined between iron oxide surfaces. When the Optimized FF was employed, the amide molecules were pulled closer to the surface and the orientation of the headgroups was more similar to that observed in the DFT calculations compared to the Original FF. The Optimized FF proposed here facilitates classical MD simulations of amide-iron oxide interfaces in which the interactions are representative of accurate DFT calculations.</div>

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Mechanistic insight into H2-mediated Ni surface diffusion and deposition to form branched Ni nanocrystals: a theoretical study

Physical Chemistry Chemical Physics ◽

10.1039/d0cp03126g ◽

2020 ◽

Vol 22 (41) ◽

pp. 23869-23877

Author(s):

Yan Li ◽

Ning Liu ◽

Chengna Dai ◽

Ruinian Xu ◽

Bin Wu ◽

...

Keyword(s):

Density Functional Theory ◽

Dft Calculations ◽

Ab Initio ◽

Surface Diffusion ◽

Density Functional ◽

Theoretical Study ◽

Functional Theory ◽

Mechanistic Insight ◽

Insight Into

Present work investigates the kinetic role of H2 during Ni surface diffusion and deposition to generate branched Ni nanostructures by employing density functional theory (DFT) calculations and ab initio molecule dynamic (AIMD) simulations.

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Hydrogen Bond Interaction of Ascorbic Acid with Urea: Experimental and Theoretical Study

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2018-1177 ◽

2019 ◽

Vol 233 (8) ◽

pp. 1061-1072 ◽

Cited By ~ 2

Author(s):

Peng Peng ◽

Ping Zhang ◽

Huiting Ma ◽

Cuiping Zhai

Keyword(s):

Density Functional Theory ◽

Ascorbic Acid ◽

Density Functional ◽

Theoretical Study ◽

Natural Bond Orbital ◽

Hydrogen Atoms ◽

Hydrogen Bond Interaction ◽

Functional Theory ◽

Interaction Sites ◽

Theoretical Results

Abstract The interactions of ascorbic acid (AA) with urea were investigated by using the cyclic voltammetry, density functional theory, atoms in molecules and natural bond orbital analyses. The experimental and theoretical results show that the hydrogen bonds are formed between AA and urea, wherein the mainly interaction sites are the hydrogen atoms on enediol of AA and the oxygen atom on carbonyl of urea. The electrochemical behavior of AA was significantly affected by above interactions.

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Theoretical study on nanostructural modifications of the Si(111) surface

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633619500056 ◽

2019 ◽

Vol 18 (01) ◽

pp. 1950005

Author(s):

Yue-Hang Dong ◽

Xiao-Hui Liu ◽

Wan-Sheng Su ◽

Li-Zhen Zhao ◽

Qing-Jun Zang ◽

...

Keyword(s):

Density Functional Theory ◽

Optical Properties ◽

Optical Absorption ◽

Dft Calculations ◽

Electronic Structures ◽

Density Functional ◽

Theoretical Study ◽

Surface Modifications ◽

Thermal Stabilities ◽

Functional Theory

Modified Si(111) surface with designed nanostructural modifications including grown pits, nanobars and nanoislands as well as deposited hill-, diamond- and cage-like nanoclusters were studied using density-functional theory (DFT) calculations. The thermal stabilities, electronic structures and optical properties of these various nanostructural modifications of the Si(111) surface were calculated and discussed. The results indicate that the optical absorption of the modified Si(111) surface can be enhanced by these surface modifications especially when depositing diamond-like nanoclusters on the surface.

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