This package is named *AtomicReactions*.
In atomic physics, the electron shells and their behaviour under collisions with electrons or photons are the scope of the research field. 
This package provides commands to create term schemes for basic atomic reactions of the electron shells. 
For electron-impact single ionisation a number of specific reactions are possible which are: 

- Direct ionisation (DI)
- Excitation auto-ionisation (EA)
- Resonant double auto-ionisation (REDA)
- Resonant auto-double-ionisation (READI)


For double and multiple ionisation dedicated processes are possible like *ionisation auto-ionisation*. 
Since the shell of an atom is a concept one can illustrate nicely by a picture, the goal of this package is to provide TikZ \cite{tikz} drawings of those processes mentioned above. 
They are based on the drawings of Müller (2008) to illustrate the behaviour of the electrons in the shell for the different reactions possible. 

This package also provides a classical illustration for the atomic model by Niels Bohr \cite{bohr1913}, which shows the shells and electrons in dependence of occupation and chemical element.
The approach here is easy. In case you want to have more customisation options, please try the package *bohr* by Clemens Niederberger. Both packages can be used at the same time. 