### Table of Contents

**Mathematical background.**

Symbolics- Principles of quantum mechanics- Approximate methods of quantum mechanics- Angular momentum- Tensor properties- Molecular symmetry.** Summary. References.**

**Macroscopic magnetic properties.**

Magnetic quantities- Thermodynamic relationships- Alternating fields- Demagnetisation correction- Overview of magnetic susceptibilities- Statistical thermodynamics.** Summary. References.**

**Microscopic magnetic properties.**

Magnetic parameters- Electromagnetic potential- The Schrödinger equation in a magnetic field- Inclusion of the electron spin- Inclusion of the nuclear spin- Inclusion of the electron and nuclear spins- The effect of nuclear structure.** Summary. References.**

**Relativistic approach.**

Quantisation of relativistic Hamilton function- The Dirac equation for a free electron- The Dirac equation for an electron in the electromagnetic field- Approximate solution of the Dirac equation- Relativistic one-electon Hamiltonian terms- Relativistic two-electron Hamiltonian terms- The magnetogyric factor for the electron- Molecular Hamiltonian terms.** Summary. References.**

**Evaluation of magnetic parameters.**

Methods- Magnetic susceptibility- The *g*-tensor- The *D*-tensor.** Summary. References.**

**Temperature dependence of magnetic susceptibility.**

Susceptibility formulae- Numerical aspects- Optimisation algorithms- Fitting the magnetic susceptibility.** Summary. References.**

**Types of magnetic materials.**

Diamagnetism- Paramagnetism- Cooperative ordering.**Summary. References.**

**Single magnetic centres.**

Free atom- Crystal field theory- Magnetic properties of free ions- Zero-field splitting- Orbital angular momentum contribution- Other interactions in mononuclear systems.** Summary. References.**

**Spin crossover systems.**

Identification of spin transition- Models of spin transition- Properties of spin crossover systems.** Summary. References.**

**Dinuclear systems.**

Exchange interaction- Isotropic exchange in dinuclear systems- Non-isotropic exchange in dinuclear systems- Other interactions in dinuclear systems.** Summary. References.**

**Clusters.**

General strategy- Trinuclear clusters- Tetranuclear clusters- Chain systems- Double exchange.** Summary. References.**

**Appendices.**

Units and important definitions- Angular momentum matrices - Special Formulae- Pascal constants for diamagnetic susceptibility-Program for 3*j, *6*j,* and 9*j-*symbols- Program for low-spin to high-spin conversion.

**Subject index.**