Representation of Molecular Systems in Quantarhei

Here we describe how molecular systems are represented in Quantarhei. We distinguish three different components of molecular open quantum systems.

Molecules

At the center of everything are Molecules as the basic building blocks. They are characterized by the spatial structure (often in a limited representation which comprises e.g. just their positions and transition dipole moments) and energy level structure. Most often we represent molecules as two-level systems.

Molecular Environment

Unless the molecules are in gas phase, they are naturally embedded is some kind of an environment. Actually, even in gaas phases the molecules interact with electromagnetic field, and we can therefore still consider them embedded in an environment, and therefore open.