270009 VO+UE Technology of materials and chemical binding (2019S)

The first part of the lecture by R. Podloucky deals with the basics of
chemical bonding. Starting with a short discussion of the Schödinger
equation and its formulation in the framework of density-functional
theory, the thermodynamic and quantum-mechanical stabilization is
defined. The course continues with a short discussion of other types of bonding.

In the second part of the lecture P. Herzig deals with physical
quantities in solids which are direction-dependent. In the simplest
cases vectors can be used, in the more complicated cases tensors of
various "ranks" are required. Examples for tensors of rank 2 are
conductivity, stress and strain, tensors of rank 4 are the quantities
needed for the description of elastic properties of solids. It is shown
how different vectorial and tensorial properties depend on the crystal
symmetry and how they can be calculated on the basis of
density-functional theory.

Continuing along these lines the last part
of the course R. Eibler is concerned with lattice vibrations
("phonons"). These are important, because they provide information on
the (vibrational) stability of solids and make it possible to calculate
the temperature dependence of the thermodynamic functions caused by the
lattice vibrations.