Editing Ionization (section)

{{short description|Process by which atoms or molecules acquire charge by gaining or losing electrons}}
{{Redirect|Ionisation|the musical composition|Ionisation (Varèse)}}
[[File:Aurora in Abisko near Torneträsk.jpg|alt=The solar wind moving through the magnetosphere alters the movements of charged particles in the Earth's thermosphere or exosphere, and the resulting ionization of these particles causes them to emit light of varying colour, thus forming auroras near the polar regions.|thumb|201x201px|The [[solar wind]] moving through the [[magnetosphere]] alters the movements of charged particles in the [[Earth]]'s [[thermosphere]] or [[exosphere]], and the resulting '''ionization''' of these particles causes them to emit light of varying color, thus forming [[auroras]] near the [[Polar regions of Earth|polar regions]].]]
'''Ionization''' or '''ionisation''' is the process by which an [[atom]] or a [[molecule]] acquires a negative or positive [[Electric charge|charge]] by gaining or losing [[electron]]s, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an [[ion]]. Ionization can result from the loss of an electron after collisions with [[subatomic particle]]s, collisions with other atoms, molecules, electrons, [[positron]]s,<ref>{{Cite book |last1=Machacek |first1=J.R. |title=Springer Handbook of Atomic, Molecular, and Optical Physics. Springer Handbooks |last2=McEachran |first2=R.P. |last3=Stauffer |first3=A.D. |date=2023 |publisher=Springer |isbn=978-3-030-73892-1 |chapter=Positron Collisions |doi=10.1007/978-3-030-73893-8_51}}</ref> [[proton]]s, [[antiproton]]s,<ref>{{Cite journal |last1=Kirchner |first1=Tom |last2=Knudsen |first2=Helge |date=2011 |title=Current status of antiproton impact ionization of atoms and molecules: theoretical and experimental perspectives |url=https://iopscience.iop.org/article/10.1088/0953-4075/44/12/122001/pdf |journal=Journal of Physics B: Atomic, Molecular and Optical Physics |volume=44 |issue=12 |pages=122001 |doi=10.1088/0953-4075/44/12/122001|url-access=subscription }}</ref> and ions,<ref>{{Cite book |last=Brandsen |first=B.H. |title=Atomic Collision Theory |publisher=Benjamin |year=1970 |isbn=9780805311808}}</ref><ref>{{Cite book |last1=Stolterfoht |first1=N |title=Electron Emission in Heavy Ion-Atom Collisions |last2=DuBois |first2=R.D. |last3=Rivarola |first3=R.D. |publisher=Springer-Verlag |year=1997 |isbn=978-3-642-08322-8}}</ref><ref>{{Cite book |last=McGuire |first=J.H. |title=Electron correlation dynamics in atomic collisions |publisher=Cambridge University Press |year=1997 |isbn=9780521480208}}</ref><ref>{{Cite book |last=Eichler |first=J. |title=Lectures on Ion-Atom Collisions: From Nonrelativistic to Relativistic Velocities |publisher=Elsevier |year=2005 |isbn=9780444520470}}</ref><ref>{{Cite book |last1=Bransden |first1=B.H. |title=Charge Exchange and the Theory of Ion-Atom Collisions |last2=McDowell |first2=M.R.C. |publisher=Clarendon Press; Oxford University Press |year=1992 |isbn=9780198520207}}</ref><ref>{{Cite book |last1=Janev |first1=R.K. |title=Physics of Highly Charged Ions |last2=Presnyakov |first2=L.P. |last3=Shevelko |first3=V.P. |publisher=Springer |year=1985 |isbn=978-3-642-69197-3}}</ref><ref>{{Cite book |last=Schulz |first=Michael |title=Ion-Atom Collisions The Few-Body Problem in Dynamic Systems |publisher=De Gruyter |year=2019 |isbn=9783110579420 |doi=10.1515/9783110580297}}</ref><ref>{{Cite book |last=D. |first=Belkic |title=Quantum Theory of High-Energy Ion-Atom Collisions |publisher=CRC Press |year=2009 |isbn=978-1-58488-728-7}}</ref> or through the interaction with [[electromagnetic radiation]].<ref>{{Cite book |last=Schmelcher |first=P. |title=Atoms and Molecules in Strong External Fields |last2=Schweitzer |first2=W. |publisher=Kulver Academic Publishers |year=2002 |isbn=0-306-45811-X}}</ref> [[Heterolytic bond cleavage]] and heterolytic [[substitution reaction]]s can result in the formation of ion pairs. Ionization can occur through radioactive decay by the [[internal conversion]] process, in which an excited nucleus transfers its energy to one of the [[inner-shell electrons]] causing it to be ejected.