Applications of Group Theory in Solid State Physics

Lecturer:

Zdeněk Potůček (gar.)

Tutor:

Supervisor:

Department of Solid State Engineering

Synopsis:

Consideration of atomic system symmetry allows, without any quantitative calculations, rigorously and precisely determine how many energy states there are and what interactions and transitions between them may occur. Therefore, the main purpose of this course is to describe the methods by which we can extract the information on the object that symmetry alone will provide. The application of these methods is illustrated by an example of molecular orbitals, inner orbitals of atoms in the crystal field environment, normal modes of molecular vibrations, and selection rules for optical absorption transitions.

Requirements:

Syllabus of lectures:

1. Definitions and theorems of group theory. 2. Molecular symmetry. 3. The symmetry point groups, classes of symmetry operations. 4. Transformation of tensors. 5. Representations of groups - reducible and irreducible representations, properties of irreducible representations. 6. Character tables. 7. Wave functions as bases for irreducible representations. 8. The direct product and its use for identifying nonzero matrix elements in quantum mechanics. 9. Molecular orbital theory - transformation properties of atomic orbitals, complete and incomplete projection operator, molecular orbitals for sigma and pi bonding. 10. Ligand field theory, splitting of the terms of free atoms and ions in a crystalline environment. 11. Construction of energy level diagrams for ions in a crystalline environment, the method of descending symmetry. 12. Selection rules and polarizations of optical transitions.

Syllabus of tutorials:

Study Objective:

Knowledge:^^Theory of group representations and its application to determination of molecular orbitals, energy levels of ions in a crystalline environment, normal modes of molecular vibrations, and probability of optical absorption transitions. ^^Skills:^^Ability to obtain attainable information about physical properties of atomic system (molecule, crystal) arising from its symmetry alone.

Study materials:

Key references:^^ [1]. F. A. Cotton: Chemical applications of group theory, John Willey and Sons, New York, 1990. ^^Recommended references:^^ [2]. M. S. Dresselhaus, G. Dresselhaus, A. Jorio: Group theory: application to the physics of condensed matter, Springer-Verlag, Berlin, 2008.

Note:

Time-table for winter semester 2011/2012:

Time-table is not available yet

Time-table for summer semester 2011/2012:

Time-table is not available yet

The course is a part of the following study plans:

• FNSPE Prospectus BC level (!)