Editing Zeeman effect (section)

== Demonstrations ==
[[File:Zeeman effect demo.svg|thumb|Diagram of a Zeeman effect demonstration]]
The Zeeman effect can be demonstrated by placing a sodium vapor source in a powerful electromagnet and viewing a sodium vapor lamp through the magnet opening (see diagram).  With magnet off, the sodium vapor source will block the lamp light; when the magnet is turned on the lamp light will be visible through the vapor.

The sodium vapor can be created by sealing sodium metal in an evacuated glass tube and heating it while the tube is in the magnet.<ref name=demo_followup>{{Citation |title=Candle flame is repelled by magnets (and Zeeman follow-up) |url=https://youtube.com/watch/JV4Fk3VNZqs?si=U20jHpiTGt0G71pu |access-date=2024-02-27 |language=en}}</ref>

Alternatively, salt ([[sodium chloride]]) on a ceramic stick can be placed in the flame of [[Bunsen burner]] as the sodium vapor source. When the magnetic field is energized, the lamp image will be brighter.<ref>{{Citation |title=Candle flame is repelled by magnets (and Zeeman follow-up) |url=https://youtube.com/watch/JV4Fk3VNZqs?si=U20jHpiTGt0G71pu |access-date=2024-02-27 |language=en}}</ref> However, the magnetic field also affects the flame, making the observation depend upon more than just the Zeeman effect.<ref name=demo_followup/> These issues also plagued Zeeman's original work; he devoted considerable effort to ensure his observations were truly an effect of magnetism on light emission.<ref>{{Cite journal |last=Kox |first=A J |date=1997-05-01 |title=The discovery of the electron: II. The Zeeman effect |url=https://iopscience.iop.org/article/10.1088/0143-0807/18/3/003 |journal=European Journal of Physics |volume=18 |issue=3 |pages=139–144 |doi=10.1088/0143-0807/18/3/003 |bibcode=1997EJPh...18..139K |s2cid=53414643 |issn=0143-0807}}</ref>

When salt is added to the Bunsen burner, it [[Dissociation (chemistry)|dissociates]] to give [[sodium]] and [[chloride]]. The sodium atoms get excited due to [[Photon|photons]] from the sodium vapour lamp, with electrons excited from 3s to 3p states, absorbing light in the process. The sodium vapour lamp emits light at 589nm, which has precisely the energy to excite an electron of a sodium atom. If it was an atom of another element, like chlorine, shadow will not be formed.<ref>{{Cite journal |last1=Suzuki |first1=Masatsugu Sei |last2=Suzuki |first2=Itsuko S. |date=2011 |title=Lecture Note on Senior Laboratory Zeeman effect in Na, Cd, and Hg |url=https://www.researchgate.net/publication/269929968 |journal=ResearchGate}}</ref>{{verification failed|date=February 2024}} When a magnetic field is applied, due to the Zeeman effect the [[spectral line]] of sodium gets split into several components. This means the energy difference between the 3s and 3p [[Atomic orbital|atomic orbitals]] will change. As the sodium vapour lamp don't precisely deliver the right frequency anymore, light doesn't get absorbed and passes through, resulting in the shadow dimming. As the magnetic field strength is increased, the shift in the spectral lines increases and lamp light is transmitted.{{Cn|date=February 2024}}