Journal ArticleDOI
Chemistry with ADF
G. te Velde,F.M. Bickelhaupt,Evert Jan Baerends,C. Fonseca Guerra,S. J. A. van Gisbergen,J.G. Snijders,T. Ziegler +6 more
Reads0
Chats0
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, 2001read more
Citations
More filters
Journal ArticleDOI
Nucleophilic substitution at silicon (SN2@Si) via a central reaction barrier
TL;DR: The results show that the nature of the SN2 reaction barrier is in essence steric, but that it can be modulated by electronic factors.
Journal ArticleDOI
Ph Modulates the Quinone Position in the Photosynthetic Reaction Center from Rhodobacter Sphaeroides in the Neutral and Charge Separated States.
Juergen Koepke,Eva-Maria Krammer,Astrid R. Klingen,Pierre Sebban,G. Matthias Ullmann,Günter Fritzsch +5 more
TL;DR: These extended proton-transfer pathways, ending at either of the two oxo-groups of QB in its proximal position, provide additional evidence that ring-flipping is not required for complete protonation of QB upon reduction.
Book ChapterDOI
Ab Initio Quantum Simulation in Solid State Chemistry
TL;DR: In this article, the authors compare the complexity of real crystals with the smallest molecule, H2, and show that the latter has a much greater complexity than the latter in terms of complexity of a real crystal.
Journal ArticleDOI
Understanding chemical reactivity using the activation strain model.
Pascal Vermeeren,Stephanie C. C. van der Lubbe,Célia Fonseca Guerra,Célia Fonseca Guerra,F. Matthias Bickelhaupt,F. Matthias Bickelhaupt,Trevor A. Hamlin +6 more
TL;DR: This protocol aims to provide chemists with the tools to implement a powerful and robust method for analyzing and understanding any chemical reaction using PyFrag 2019, and provides step-by-step instructions that can serve as a guide for carrying out the analysis of any given reaction of interest within hours to days, depending on the size of the molecular system.
Journal ArticleDOI
Analysis of Aromatic Delocalization: Individual Molecular Orbital Contributions to Nucleus-Independent Chemical Shifts
Thomas Heine,Paul von Ragué Schleyer,Clémence Corminboeuf,Gotthard Seifert,Roman Reviakine,Jacques Weber +5 more
TL;DR: In this article, individual molecular orbital contributions to the magnetic shielding of atoms as well as to the nucleus-independent chemical shifts (NICS) of aromatic compounds can be computed by the widely used gauge-including atomic orbital (GIAO) method.
References
More filters
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.
Journal ArticleDOI
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.
Journal ArticleDOI
Self-Consistent Equations Including Exchange and Correlation Effects
Walter Kohn,L. J. Sham +1 more
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.
Journal ArticleDOI
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.
Journal ArticleDOI
Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation.
John P. Perdew,J. A. Chevary,S. H. Vosko,Koblar A. Jackson,Mark R. Pederson,David J. Singh,Carlos Fiolhais +6 more
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.