The general problem of separability in quantum chemistry. Groups of elec-trons and their interaction. The orthogonality problem. Sigma-Pi separability. Core-Valence separability. The need of effective core-valence potentials (ECP). Core-valence interaction in heavy atoms and relativistic effects.

Objectives of the program: Understanding the theoretical background of using the ECP approach in computational quantum chemistry. What it can be computed (and what not) on the basis of ECP approaches. ECP for molecular systems and solid-state-like systems.

Evaluation: YES