In the following section XH stands for any hydrogen compound,  e.g. CH- and NH-compounds.
* Thermal dissociation: gaseous hydrogen molecules are being dissociated at temperatures above 3000 K e.g. in a plasma. At temperatures above 3500 K H und O are dissociated.
* electron impact dissociation: 
The density of radicals scales with the electron density and higher gas and electron temperatures (thermal dissociation and electron impact).
* ion impact dissociation: <br />
* dissociative electron attachment: 
This process generates negative ions as well as neutral particles. The collision electron is captured by collision excitation. The energy difference between the ground state and the excited state dissociates the molecule. The electron-induced dissociation of water depends on the electron temperature, which influences the ratio of the OH density (n_OH) to the electron density (n_e) significantly. The maximum OH density is reached in the early afterglow when the electron temperature (T_e) is low.
* Photoionisation:<br> High-energy photons dissociate molecules
* Solvated electrons:<br> Reducing agent in liquid