## Wikipedia - Gas-phase ion chemistry (en) Wikipedia - Ion source (en) Wikipedia - Ionisation de Penning (fr) Wikipedia - Penning ionisering (no) Wikipedia - Penning ionization (en) Penning gas mixture

https://doi.org/10.1351/goldbook.P04476
A Penning gas mixture consists of a rare gas containing impurity atoms possibly at very low concentrations. The impurity atoms have an @[email protected] $$V_{\text{ion}}$$ which is lower than or equal to the @[email protected] potential ($$V_{\text{meta}}$$) of the parent noble gas. The Penning effect in a Penning gas mixture is the @[email protected] by charge transfer (charge exchange) during collision between a @[email protected] atom and a neutral atom which decreases the average energy to form an @[email protected], e.g.
P04476.png
In a glow discharge, this results in an increase of the the @[email protected] @[email protected] (Townsend first @[email protected]), a decrease in breakdown potential and a lowering of the @[email protected] fall potential. The magnetic Penning effect describes the increase of the @[email protected] @[email protected] of gas in a @[email protected] resulting from the helical (spiral) movement of electrons in a magnetic field placed normal to the @[email protected]@[email protected] electrical field.
Source:
Orange Book, 2nd ed., p. 148 [Terms] [Book]