2. Notions of atomic structure and spectroscopy

2.1 General

The emission and absorption spectra of atoms are made up of a number of lines that are more or less fine, depending on the state of the medium in question.

The simplest atom, hydrogen, emits a spectrum that is itself relatively simple, while the spectra of heavy atoms are extremely complex. The spectrum of the hydrogen atom was thus the focus of the first attempts at theoretical interpretation, and has played an extremely important role in this respect.

Further information can be found in the reference works [