Ionization

Ionization (or ionisation, see American and British English spelling differences) is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or ions. In the case of ionization of a gas, ion pairs are created consisting of a free electron and a positive ion.

Read more about Ionization:  Types of Ionization, Classical Ionization, Quantum Ionization, Dissociation – Distinction