Dft Teoria Funcional

Chem. Rev. 2003, 103, 1793−1873

1793

Conceptual Density Functional Theory
P. Geerlings,*,† F. De Proft,† and W. Langenaeker‡
Eenheid Algemene Chemie, Faculteit Wetenschappen, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium, and Department of Molecular Design and Chemoinformatics, Janssen Pharmaceutica NV, Turnhoutseweg 30, B-2340 Beerse, Belgium Received April 2,2002

Contents
I. Introduction: Conceptual vs Fundamental and Computational Aspects of DFT II. Fundamental and Computational Aspects of DFT A. The Basics of DFT: The Hohenberg−Kohn Theorems B. DFT as a Tool for Calculating Atomic and Molecular Properties: The Kohn−Sham Equations C. Electronic Chemical Potential and Electronegativity: Bridging Computational and Conceptual DFT III. DFT-BasedConcepts and Principles A. General Scheme: Nalewajski’s Charge Sensitivity Analysis B. Concepts and Their Calculation 1. Electronegativity and the Electronic Chemical Potential 2. Global Hardness and Softness 3. The Electronic Fukui Function, Local Softness, and Softness Kernel 4. Local Hardness and Hardness Kernel 5. The Molecular Shape FunctionsSimilarity 6. The Nuclear Fukui Function and ItsDerivatives 7. Spin-Polarized Generalizations 8. Solvent Effects 9. Time Evolution of Reactivity Indices C. Principles 1. Sanderson’s Electronegativity Equalization Principle 2. Pearson’s Hard and Soft Acids and Bases Principle 3. The Maximum Hardness Principle IV. Applications A. Atoms and Functional Groups B. Molecular Properties 1. Dipole Moment, Hardness, Softness, and Related Properties 2.Conformation 3. Aromaticity C. Reactivity 1. Introduction 2. Comparison of Intramolecular Reactivity Sequences 1793 1795 1795 1796 1797 1798 1798 1800 1800 1802 1807 1813 1814 1816 1819 1820 1821 1822 1822 1825 1829 1833 1833 1838 1838 1840 1840 1842 1842 1844 V. VI. VII. VIII. IX.

3. Comparison of Intermolecular Reactivity Sequences 4. Excited States D. Clusters and Catalysis Conclusions Glossary of MostImportant Symbols and Acronyms Acknowledgments Note Added in Proof References

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I. Introduction: Conceptual vs Fundamental and Computational Aspects of DFT
It is an understatement to say that the density functional theory (DFT) has strongly influenced the evolution of quantum chemistry during the past 15 years; the term “revolutionalized” is perhapsmore appropriate. Based on the famous Hohenberg and Kohn theorems,1 DFT provided a sound basis for the development of computational strategies for obtaining information about the energetics, structure, and properties of (atoms and) molecules at much lower costs than traditional ab initio wave function techniques. Evidence “par excellence” is the publication of Koch and Holthausen’s book, Chemist’sGuide to Density Functional Theory,2 in 2000, offering an overview of the performance of DFT in the computation of a variety of molecular properties as a guide for the practicing, not necessarily quantum, chemist. In this sense, DFT played a decisive role in the evolution of quantum chemistry from a highly specialized domain, concentrating, “faute de mieux”, on small systems, to part of a toolboxto which also different types of spectroscopy belong today, for use by the practicing organic chemist, inorganic chemist, materials chemist, and biochemist, thus serving a much broader scientific community. The award of the Nobel Prize for Chemistry in 1998 to one, if not the protagonist of (ab initio) wave function quantum chemistry, Professor J. A. Pople,3 and the founding father of DFT,Professor Walter Kohn,4 is the highest recognition of both the impact of quantum chemistry in present-day chemical research and the role played by DFT in this evolution. When looking at the “story of DFT”, the basic idea that the electron density, F(r), at each point r determines the ground-state properties of an atomic, molecular, ... system goes back to the early work of

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