Contents

• Introduction
• The importance of the total energy
• The total energy within density functional theory
  • Electrostatics
  • Quantum mechanics
  • Variational principle
• Kohn-Sham equations
  • Basics of the calculus of variations
  • Derivative of a real function of a complex variable and its conjugate
  • Kohn-Sham Equations
  • Solution of the equations
• Atomic units
• References
• About this document ...