Density functional theory (DFT) and Hartree–Fock (HF) calculations of potential p–vinylbenzyl chloride-based macroinitiator for atom transfer radical polymerization

2016 ◽  
Vol 94 (3) ◽  
pp. 290-304 ◽  
Author(s):  
Feride Akman
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Potential Energy ◽  
Density Functional ◽  
Energy Surface ◽  
Functional Theory ◽  
Hartree Fock ◽  
Experimental Values ◽  
Good Agreement ◽  
Hf Calculations

The spectroscopic properties of poly (styrene–co–p–vinylbenzyl chloride) (poly (St-co-VBC)) were investigated by Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopic techniques. The molecular geometry and vibrational frequencies of macroinitiator, poly (St-co-VBC), were calculated by using density functional theory (DFT) and Hartree–Fock (HF) methods with 6–31 G+ (d, p) as a basis set. Calculated theoretical values are shown to be in good agreement with that of experimental values. An excellent harmony between the two data sets was verified. Besides, the experimental data of macroinitiator were compared with experimental data of its corresponding monomers such as St and VBC. The dimer and trimer forms of macroinitiator are used as significant contributions for getting an accurate interpretation of the experimental frequencies of poly (St-co-VBC). The results revealed that the change from St and VBC to poly (St-co-VBC) should be characterized by the disappearance of the CH2=CH bonds of the vinyl group and the appearance of the aliphatic C–H and CH2 bonds. The geometrical parameters, Mulliken atomic charges and frontier molecular orbitals energies were also calculated using the same theoretical methods. The chemical shifts were calculated by using the gauge–including atomic orbital method and all the theoretically predicted values were shown to be in good agreement with experimental values. Molecular orbital properties, molecular electrostatic potential, and the potential energy surface for the atom transfer radical polymerization (ATRP) of the macroinitiator were studied with DFT and HF calculations. The potential energy surface of the ATRP initiator is decided by their electronic effect and steric hindrance effect simultaneously.

scholarly journals A computational study of the fluctional behaviour of group 14 substituted ortho-semiquinone radicals

2011 ◽  
Vol 89 (2) ◽  
pp. 235-240 ◽  
Author(s):  
K. U. Ingold ◽  
Gino A. DiLabio
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Rate Constant ◽  
Density Functional ◽  
Computational Study ◽  
Group 14 ◽  
Functional Theory ◽  
Semiquinone Radicals ◽  
Experimental Values ◽  
Good Agreement

The dynamics of the 1,4-migration of some O-substituted 3,5-di-tert-butyl-ortho-semiquinone radicals have been calculated by density-functional theory (DFT). There is very good agreement in the rate constant and Arrhenius parameters between these calculations and experimental values for migration of H, D, and the Me3Si group. For the Me3Sn group, the calculations indicate an incredibly fast migration (k293K = 2.0 × 1012 s–1), a result that is consistent with experimental data (k293K > 109 s–1). Other O-substituents examined by DFT and compared with experimental data were H3C and Me2ClSn.

THE H2NO POTENTIAL ENERGY SURFACE EXPLORED WITH HIGH LEVEL AB INITIO AND DENSITY FUNCTIONAL THEORY METHODS

2007 ◽  
Vol 06 (03) ◽  
pp. 549-562
Author(s):  
ABRAHAM F. JALBOUT
Keyword(s):  
Density Functional Theory ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Density Functional ◽  
Energy Surface ◽  
Hybrid Methods ◽  
Transition States ◽  
Basis Set ◽  
Functional Theory ◽  
High Level

The transition states for the H 2 NO decomposition and rearrangements mechanisms have been explored by the CBS-Q method or by density functional theory. Six transition states were located on the potential energy surface, which were explored with the Quadratic Complete Basis Set (CBS-Q) and Becke's one-parameter density functional hybrid methods. Interesting deviations between the CBS-Q results and the B1LYP density functional theory lead us to believe that further study into this system is necessary. In the efforts to further assess the stabilities of the transition states, bond order calculations were performed to measure the strength of the bonds in the transition state.

scholarly journals Double-well potential energy surface in the interaction between h-BN and Ni(111)

2019 ◽  
Vol 21 (21) ◽  
pp. 10888-10894
Author(s):  
Jorge Ontaneda ◽  
Francesc Viñes ◽  
Francesc Illas ◽  
Ricardo Grau-Crespo
Keyword(s):  
Density Functional Theory ◽  
Potential Energy ◽  
Density Functional ◽  
Energy Surface ◽  
Density Functional Theory Calculations ◽  
Dispersion Forces ◽  
Local Correlation ◽  
Functional Theory ◽  
Non Local ◽  
Double Well Potential

Density functional theory calculations with non-local correlation functionals, properly accounting for dispersion forces, predict the presence of two minima in the interaction energy between h-BN and Ni(111).

The Variediene-Forming Carbocation Cyclization/Rearrangement Cascade

2017 ◽  
Vol 70 (4) ◽  
pp. 362 ◽  
Author(s):  
Young J. Hong ◽  
Dean J. Tantillo
Keyword(s):  
Density Functional Theory ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Density Functional ◽  
Energy Surface ◽  
Functional Theory ◽  
Density Functional Theory Computations

An energetically viable (on the basis of results from density functional theory computations) pathway to the diterpene variediene is described. Only one of the three secondary carbocations along this pathway is predicted to be a minimum on the potential energy surface.

scholarly journals Using a monomer potential energy surface to perform approximate path integral molecular dynamics simulation of ab initio water at near-zero added cost

2019 ◽  
Vol 21 (1) ◽  
pp. 409-417 ◽  
Author(s):  
Daniel C. Elton ◽  
Michelle Fritz ◽  
Marivi Fernández-Serra
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Molecular Dynamics Simulation ◽  
Potential Energy ◽  
Path Integral ◽  
Liquid Water ◽  
Density Functional ◽  
Energy Surface ◽  
Dynamics Simulation ◽  
Functional Theory

We present a new approximate method for doing path integral molecular dynamics simulation with density functional theory and show the utility of the method for liquid water.

Density Functional Theory Study: Interactions of Lithium-Montmorillonite with Poly(Ethylene Oxide) as Preliminary Investigation of Lithium Polymer Conductivity

2014 ◽  
Vol 893 ◽  
pp. 790-793
Author(s):  
Muhammad Naufal Lintangpradipto ◽  
Triati Dewi Kencana Wungu ◽  
Ahmad H. Lubis ◽  
Hermawan Kresno Dipojono ◽  
Nugraha
Keyword(s):  
Density Functional Theory ◽  
Ethylene Oxide ◽  
Potential Energy ◽  
Density Functional ◽  
Preliminary Investigation ◽  
Energy Curve ◽  
Functional Theory ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Good Agreement

In this study, the interactions between poly (ethylene oxide) (PEO) and lithium-montmorillonite (LiMMT) have been investigated using density functional theory (DFT) calculation. The results of calculations show that the adsorption process of PEO on the LiMMT surface is physisorption with adsorption energy of -0.063 eV. This observation is consistent with the results of our calculations on PES (Potential Energy Surface) and PEC (Potential Energy Curve). The formation of space between PEO and LiMMT are found in range of 3.4 - 4.2 Å which are in good agreement with experimental results.

scholarly journals Calculation of the Detonation State of HN3 with Quantum Accuracy

2020 ◽  
Author(s):  
Cong Huy Pham ◽  
Rebecca Lindsey ◽  
Laurence E. Fried ◽  
Nir Goldman
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Potential Energy ◽  
Force Field ◽  
Density Functional ◽  
Energy Surface ◽  
Detonation Properties ◽  
Training Set ◽  
Functional Theory ◽  
Wide Range

<div>HN<sub>3</sub> is a unique liquid energetic material that exhibits ultrafast detonation chemistry and a transition to metallic states during detonation. We combine the ChIMES many-body reactive force field and the extended-Lagrangian multiscale shock technique (MSST) molecular dynamics method to calculate the detonation properties of HN<sub>3</sub> with the accuracy of Kohn-Sham density-functional theory. ChIMES is based on a Chebyshev polynomial expansion and can accurately reproduce density-functional theory molecular dynamics (DFT-MD) simulations for a wide range of unreactive and decomposition conditions of liquid HN<sub>3</sub>. We show that addition of random displacement configurations and the energies of gas-phase equilibrium products in the training set allows ChIMES to efficiently explore the complex potential energy surface. Schemes for selecting force field parameters and the inclusion of stress tensor and energy data in the training set are examined. Structural and dynamical properties, as well as chemistry predictions for the resulting models are benchmarked against DFT-MD. We demonstrate that the inclusion of explicit four-body energy terms is necessary to capture the potential energy surface across a wide range of conditions. The present force field, which was fit to a balance of forces, energies, and stress tensors yields excellent agreement with DFT, while exhibiting an orders-of-magnitude increase in computational efficiency over DFT-MD. Our results generally retain the accuracy of DFT-MD while yielding a high degree of computational efficiency, allowing simulations to approach orders of magnitude larger time and spatial scales. The techniques and recipes for MD model creation we present allow for direct simulation of nanosecond shock compression experiments and calculation of the detonation properties of materials with the accuracy of Kohn-Sham density-functional theory.</div>

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