Molecules in Physics, Chemistry, and Biology

Density Functions and Electronic Structure.- The Molecule as a Many-Electron System: Electron Densities and Molecular Properties.- 1. Introduction.- 2. Electron Density Functions.- 3. Electronic Properties — Response.- 4. Static Response to Uniform Fields.- 5. Spin-Dependent Properties.- 6. Dynamic Response and Related Properties.- 7. Conclusion.- References.- Analysis of the Electronic Density as a Support of the Concepts of Empirical Structural Chemistry.- 1. Introduction.- 2. Partitioning of the Electronic Density.- 3. Results and Discussion.- 4. Atoms and Functional Groups.- Acknowledgements.- References.- Molecules as Ensembles of Modified Atoms.- 1. Introduction.- 2. Modified Atoms in Molecules.- 3. Conclusion.- Acknowledgements.- References.- The Physical Basis of the Lewis Electron Pair Model.- I. The Challenge and Lewis Model.- II. Properties of Density and Density Difference Functions.- III. The Localization of Electrons.- IV. The Laplacian of the Charge Density as a Basis for the Lewis Model.- V. Summary and Conclusions.- Dedication.- References.- The Chemical Bond and Model Exchange-Correlation Potentials.- 1. Introduction.- 2. The Hohenburg-Kohn Theorem and the Kohn-Sham Method.- 3. The Kinetic Energy Functional.- 4. The Exchange-Correlation Functional.- 5. Application to Chemical Systems.- 6. Problems and Prospects.- References.- Study of Chemical Bonding in Molecules: The Interest of Polarised Neutron Diffraction.- 1. Introduction.- 2. Polarised Neutron Diffraction.- 3. 3d Transition Metal Complexes.- 4. Organic Free Radicals.- 5. Conclusion.- References.- A Valence Concept for Molecular Structure and Reactions.- 1. Historical Survey.- 2. Valence Index.- 3. Normal Valence versus Sub- and Hypervalence.- 4. Subvalence.- 5. Hypervalence.- 6. Geometry Changes.- Acknowledgements.- References.- Structure and Reactivity of Organic Compounds.- On the Role of the Orbital Interaction Concept in the Interpretation of Organic Free Radical Structures and Reactivities.- 1. Introduction.- 2. Theoretical Aspects.- 3. Interpretation of Free-Radical Reactivities.- 4. A Quantitative PMO Analysis.- 5. Conclusion.- References.- Theoretical Studies on the Reactions of Free Radicals.- 1. Introduction.- 2. Thermolysis of Azoalkanes.- 3. Bimolecular Radical Combinations.- 4. Disproportionations.- 5. Conclusion.- References.- Thermochemistry and Kinetics of Ionic and Radical Reactions in the Gas Phase.- 1. Introduction.- 2. The Concept of Stabilization Energy.- 3. Thermochemistry and Kinetics of Elementary Processes.- 4. Rate Constant Calculations in Transition State Theory.- 5. Conclusions.- Acknowledgement.- References.- Hydrocarbon Radical Cations in Condensed Phases.- 1. Introduction.- 2. Generation and Stabilization of Radical Cations.- 3. Experimental Results.- 4. Theoretical Calculations.- Acknowledgements.- References.- Recent Developments in Calixarenes and their Properties.- 1. Introduction.- 2. Synthesis of Calixarenes.- 3. Chemical Transformations of Calixarenes.- 4. Conformational Properties.- 5. Inclusion Complexes.- 6. Other Types of Calixarenes and Parent Molecules.- 7. Miscellaneous.- 8. Conclusion.- References.- Theoretical Approaches to Chemical Reactions.- The Reaction-Rate Approach in Physics, Chemistry, and Biology.- 1. Introduction.- 2. General Theory.- 3. Applications to Gas-Phase Reactions.- 4. Applications to Dense-Phase Reactions.- References.- A Theoretical Study of the Unimolecular Dissociation of Diborane.- 1. Introduction.- 2. Methods.- 3. Calculations.- 4. Summary of Results.- Acknowledgements.- References.- Mode Selective Biomolecular Reactions.- 1. Introduction: Why Mode Selective Chemical Reactions?.- 2. Hydrogen Atom plus Diatomic Molecule Reactions.- 3. Elementary Hydrogen Transfer Reactions.- 4. Conclusions.- Acknowledgements.- References.- An Overview of the Theory of Chemical Reactions and Reactivity in Enzymes and Solutions.- 1. Introduction.- 2. Theory.- 3. Molecular Dynamics and Statistics of Reacting Systems.- 4. Conclusions and Perspectives.- References.