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Chemistry with ADF

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TLDR
The “Activation‐strain TS interaction” (ATS) model of chemical reactivity is reviewed as a conceptual framework for understanding how activation barriers of various types of reaction mechanisms arise and how they may be controlled, for example, in organic chemistry or homogeneous catalysis.
Abstract
We present the theoretical and technical foundations of the Amsterdam Density Functional (ADF) program with a survey of the characteristics of the code (numerical integration, density fitting for the Coulomb potential, and STO basis functions). Recent developments enhance the efficiency of ADF (e.g., parallelization, near order-N scaling, QM/MM) and its functionality (e.g., NMR chemical shifts, COSMO solvent effects, ZORA relativistic method, excitation energies, frequency-dependent (hyper)polarizabilities, atomic VDD charges). In the Applications section we discuss the physical model of the electronic structure and the chemical bond, i.e., the Kohn–Sham molecular orbital (MO) theory, and illustrate the power of the Kohn–Sham MO model in conjunction with the ADF-typical fragment approach to quantitatively understand and predict chemical phenomena. We review the “Activation-strain TS interaction” (ATS) model of chemical reactivity as a conceptual framework for understanding how activation barriers of various types of (competing) reaction mechanisms arise and how they may be controlled, for example, in organic chemistry or homogeneous catalysis. Finally, we include a brief discussion of exemplary applications in the field of biochemistry (structure and bonding of DNA) and of time-dependent density functional theory (TDDFT) to indicate how this development further reinforces the ADF tools for the analysis of chemical phenomena. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 931–967, 2001

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Citations
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Journal ArticleDOI

Charge transport in self-organized pi-stacks of p-phenylene vinylene oligomers.

TL;DR: It is shown that a significantly higher mobility can be attained if the twist angle between neighboring oligomers is reduced, and the value deduced is 3 x 10(-3) cm2/(V s) for holes and electrons, respectively.
Journal ArticleDOI

A discrete interaction model/quantum mechanical method for describing response properties of molecules adsorbed on metal nanoparticles.

TL;DR: The results show that the molecular excitations are sensitive to the local environment on the nanoparticle as well as the specific orientation of the molecule relative to the surface.
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E2 and SN2 Reactions of X− + CH3CH2X (X = F, Cl); an ab Initio and DFT Benchmark Study

TL;DR: This benchmark has been used to evaluate the performance of 31 popular density functionals, covering local-density approximation, generalized gradient approximation (GGA), meta-GGA, and hybrid density-functional theory (DFT), and best overall agreement is obtained by representatives from each of the three categories of functionals.
Journal ArticleDOI

29Si NMR in Cement: A Theoretical Study on Calcium Silicate Hydrates

TL;DR: In this paper, the NMR spectra of 29Si in cement-based materials are studied through calculations of the isotropic shielding of silicon atoms within the density functional theory, and the results show that the 29Si chemical shifts are dependent not only on the degree of condensation of the (SiO4) units, but also on the local arrangement of the charge compensating H and Ca cations.
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Correlation between Hammett Substituent Constants and Directly Calculated π-Conjugation Strength

TL;DR: The calculated values for the pi bonding between CH2(q) and C6H4R show for substituents which have pi orbitals a linear correlation with the Hammett sigma(p), sigma (+)(p), and s Sigma(m) constants.
References
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Journal ArticleDOI

Density‐functional thermochemistry. III. The role of exact exchange

TL;DR: In this article, a semi-empirical exchange correlation functional with local spin density, gradient, and exact exchange terms was proposed. But this functional performed significantly better than previous functionals with gradient corrections only, and fits experimental atomization energies with an impressively small average absolute deviation of 2.4 kcal/mol.
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Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density

TL;DR: Numerical calculations on a number of atoms, positive ions, and molecules, of both open- and closed-shell type, show that density-functional formulas for the correlation energy and correlation potential give correlation energies within a few percent.
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Self-Consistent Equations Including Exchange and Correlation Effects

TL;DR: In this paper, the Hartree and Hartree-Fock equations are applied to a uniform electron gas, where the exchange and correlation portions of the chemical potential of the gas are used as additional effective potentials.
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Density-functional exchange-energy approximation with correct asymptotic behavior.

TL;DR: This work reports a gradient-corrected exchange-energy functional, containing only one parameter, that fits the exact Hartree-Fock exchange energies of a wide variety of atomic systems with remarkable accuracy, surpassing the performance of previous functionals containing two parameters or more.
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Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation.

TL;DR: A way is found to visualize and understand the nonlocality of exchange and correlation, its origins, and its physical effects as well as significant interconfigurational and interterm errors remain.
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