Models for Bonding in Chemistry

A readable little book assisting the student in understandin, in a nonmathematical way, the essentials of the different bonds occurring in chemistry. Starting with a short, self–contained,introduction, Chapter 1 presents the essential elements of the variation approach to either total or second–order molecular energies, the system of atomic units (au) necessary to simplify all mathematical expressions, and an introductory description of the electron distribution in molecules. Using mostly a 2x2 Hückel secular equation, Chapter 2, by far the largest part of the book because of the many implications of the chemical bond, introduces a model of bonding in homonuclear and heteronuclear diatomics, multiple and delocalized bonds in hydrocarbons, and the stereochemistry of chemical bonds in polyatomic molecules, in a word, a model of the strong first–order interactions originating the chemical bond. Chapter 3 the Hückel model of the linear polyene chain is used to explain the origin of band structure in the 1–dimensional crystal. Chapter 4 deals with a simple two–state model of weak interactions, introducing the reader to understand second–order electric properties of molecules and VdW bonding between closed shells. Lastly, in Chapter 5 studies the structure of H–bonded dimers and the nature of the hydrogen bond, which has a strength intermediate between a VdW bond and a weak chemical bond. Besides a qualitative MO approach based on HOMO–LUMO charge transfer from an electron donor to an electron acceptor molecule, a quantitative electrostatic approach is presented yielding an electrostatic model working even at its simplest pictorial level. A list of alphabetically ordered references, author and subject indices complete the book.

Spis treści:
Preface
1 Mathematical Foundations
1.1 Matrices and Systems of Linear Equations
1.2 Properties of Eigenvalues and Eigenvecto rs
1.3 Variational Approximations
1.4 The Atomic Units
1.5 The Electron Distribution in Molecules
1.6 Exchange–Overlap Densities and The Chemical Bond
Part 1: Short–Range Interactions
2 The Chemical Bond
2.1 An Elementary Molecular Orbital Model
2.2 Bond Energies and Pauli Repulsions in Homonuclear Diatomics
2.3 Multiple Bonds
2.4 The Three–Centre Double Bond in Diborane
2.5 The Heteropolar Bond
2.6 Stereochemistry of Polyatomic Molecules
2.7 sp–Hybridization Effects in First–Row Hydrides
2.8 Delocalized Bonds
2.9 Appendices
3 An Introduction to Bonding in Solids
3.1 The Linear Polyene Chain
3.2 The Closed Polyene Chain
3.3 A Model for the One–Dimensional Crystal
3.4 Electronic Bands in Crystals
3.5 Insulators, Conductors, Semiconductors, and Superconductors
3.6 Appendix: The Trigonometric Identity
Part 2: Long–Range Interactions
4 The Van der Waals (VdW) Bond
4.1 Introduction
4.2 Elements of Rayleigh–Schroedinger (RS) Perturbation Theory
4.3 Molecular Interactions
4.4 The Two–State Model of Long–Range Interactions
4.5 The Van der Waals Interactions
4.6 The C6 Dispersion Coefficient for the H–H Interaction
4.7 The Van der Waals Bond
4.8 The Keesom Interaction
5 The Hydrogen Bond
5.1 A Molecular Orbital Model of The Hydrogen Bond
5.2 Electrostatic Interactions and The Hydrogen Bond
5.3 The Electrostatic Model of The Hydrogen Bond
5.4 The Rg–HF Heterodimers
References
Author Index
Subject Index