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PX3A2 Quantum Physics of Atoms

Lecturer: Martin Lees
Weighting: 10 CATS

The principles of quantum mechanics are applied to a range of phenomena in atomic physics including the operation of a laser. The module also covers perturbation theory and variational methods.


To develop the ideas of quantum theory


By the end of the module, students should be able to:

  • Use the approximate methods of quantum theory – perturbation theory (time-dependent and time-independent), variational methods
  • Explain the role of spin and the Pauli exclusion principle
  • Explain atomic spectra and the structure of the periodic table
  • Describe the operation of lasers


Revision of 2nd year quantum theory

  1. Approximation methods in quantum mechanics. Time-independent perturbation theory, non-degenerate case, ground state of helium atom, degenerate case, Stark effect in hydrogen. Variational methods: Rayleigh - Ritz, ground state of helium atom

  2. Spin-orbit coupling and the Zeeman effect. Effects of spin-orbit coupling, and the strong and weak field Zeeman effect using time-independent perturbation theory

  3. Many electron effects-indistinguishability of identical particles. Identical particles and spin; symmetric and anti-symmetric states; discussion of periodic table, ionisation energies

  4. Time-dependent perturbation theory and the lasers. Derivation of Fermi's golden rule; radiation from atoms; operation of the laser including stimulated emission and population inversion. Density matrix and Bloch equations.

Commitment: 20 lectures

Assessment: 1.5 hour examination (85%) + assessed work (15%).

Recommended Texts: S.M. McMurry, Quantum Mechanics, Addison-Wesley 1994
F Mandl, Quantum Mechanics, Wiley A.I.M. Rae, Quantum Mechanics, IOP, 2002; S. Gasiorowicz, Quantum Physics, Wiley, 2003;