Localization and Delocalization in Quantum Chemistry, Softcover reprint of the original 1st ed. 1976 Ionized and Excited States Localization and Delocalization in Quantum Chemistry Series, Vol. 2

The second volume of the proceedings of the international seminar devoted to locali· zation and delocalization in quantum chemistry is divided into four parts. The first one is mainly concerned with the localizability of electrons in ionized and exited states. The second part shows how is it possible to take advantage of the localizability of electrons to compute molecular wave-functions. The third part of the book is an homogeneous analysis of the electronic collective excitation and of the motion of excitons in organic solids. The last section is devoted to the study of the role of electron localizability in the chemical reactivity of molecules. Concluding remarks are concerned with a careful analysis of the localizability concept itself in relation with a possible interpretation of the wave-mechanics. PART I ELECTRON LOCALIZATION IN IONIZED AND EXCITED STATES APPLICATIONS OF PAIR DENSITY ANALYSIS R. CONSTANCIEL and L. ESNAULT Centre de Mecanique Ondulatoire Appliquee, Paris, France Abstract. The method of pair density analysis is applied to various kinds of calculations. We examine the influence of the quality of the wavefunction and of the nuclear configuration; the problem of hybridization is discussed, as weIl as the relations between separability and excitation.

I / Electron Localization in Ionized and Excited States.- Applications of Pair Density Analysis.- Localization and Local Phenomena in Molecular Excited and Ionized Stationary States.- Ionization and Localization.- II / Electron Localization as a Starting Point to Calculate Wave Functions.- The Reality of Some Bond Properties Additive Systems: Faraday Effect and Bond Magnetic Rotations.- The Localisability of Electrons as a Starting Point to Build Electronic Wave Functions.- On the Calculation of Wave Functions in the Theory of Loges.- Effective Molecular Hamiltonians, Pseudopotentials and Molecular Applications.- The Calculation of Intermolecular Interaction Energies in Terms of Local Contributions.- Localization, Bonds, and Physical Models of Molecular Reality.- How Does the PCILO Method Take Advantage of Localization?.- III / Excitons and Localization.- Excitons and Electronic Collective Excitations in Molecular Organic Solids.- Electronic Collective Excitations in Molecular One-Dimensional Systems. I: Optical Response, Localization and Motion of Linear Excitons.- Electronic Collective Excitations in One-Dimensional Molecular Systems. II: Motional Effects and EPR Response of Linear Triplet Excitons.- Motion of Localized Excitations in Organic Solids.- The Coupled Coherent and Incoherent Motion of Frenkel Excitons in Molecular Crystals.- Comments on Excitons and Localization.- Localized Excitons in a Fluorobenzene Crystal.- IV / Electron Localization and Chemical Reactivity.- ‘Spin Dependence’ of the Chemistry of Open-Shell Reactants.- Localized Analysis of the Stereospecificity of Concerted Reactions.- Molecular Valence States and Binding Energies.- Application of the Method of Group Density Analysis to a Study of Excited States Acid-Base Equilibria in ConjugatedMolecules.- Loge Theory and Chemical Reactivity.- Final Discussion.- Statistical and Stochastic Aspects of the Delocalization Problem in Quantum Mechanics.- Discussion of Claverie and Diner’s Paper: the Classical Limit in the Framework of Stochastic Mechanics.- Static and Dynamical Aspects of Delocalization. Electrons and Orbitals.- Index of Names.- Index of Subjects.