Quantum Chemistry: Different, but Powerful
Jernej Stare
National Institute of Cehmistry, Ljubljana, Slovenia
Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
Quantum chemistry is a powerful branch of theoretical chemistry. Based on the most
fundamental physical principles – the quantum nature of electrons – it enables accurate
prediction of a variety of physical and chemical properties of matter. As such, quantum
calculations represent powerful support for experimental studies, particularly in the cases when
experimental assessment of properties is difficult or even impossible. Due to the highly
sophisticated numerical routines, quantum chemical methods are computationally demanding
and their application is limited to models containing up to about 100 atoms, but with the
increasing power of computers they are gaining importance and have become an integral part of
research in a variety of disciplines, including biochemistry and material science.
A number of commercial and academic program packages based on quantum chemistry is
available, offering diverse possibilities for computational study of matter in both the gas and
condensed phase. While the theoretical treatment of a specific problem should often be designed
in a unique way, many fundamental routines are common with quantum chemical methods,
among the rest geometry optimization, vibrational analysis and molecular dynamics simulation.
These protocols are being used in virtually all computational studies.
An overview of quantum chemical methods will be given, briefly outlining the fundamental
mathematical foundation and presenting the most common computational routines. The popular
program packages will be introduced. Examples from the speaker’s recent work will be
introduced.
The lectures will be followed by an extensive set of practical sessions (4 days), introducing the
students to Gaussian, probably the most popular program package for quantum modeling, and
the related supporting tools (e.g., molecular graphics). The students will also get an insight into
work under the Linux environment. Selected problems related to the structure, spectroscopy and
reactivity of molecular systems will be addressed, giving the students an experience related to
their curriculum from a unique standpoint.