With the normal Zeeman effect, I think the splitting of the emission/absorbtion lines is worth [itex]\Delta E = \mu _B B m_l[/itex]. That was before they knew about the spin.(adsbygoogle = window.adsbygoogle || []).push({});

When they discovered the spin they realized that in fact the energy splitting was worth [itex]\Delta E =g_l \mu _B B m_l[/itex] where [itex]g_l=1+\frac{j(j+1)+s(s+1)-l(l+1)}{2j(j+1)}[/itex].

Now for example if I take the hydrogen atom in its ground state, [itex]g_l=2[/itex]. So that the [itex]\Delta E[/itex] is twice as big as what they thought it was before the understanding of the spin.

How could they think that their formula before the spin introduction was "ok"? I mean a factor 2 looks enormous to me. Am I missing something?

Besides, why should one use the formula for the normal Zeeman effect in -undergraduate physics- problems while it doesn't seem (at least to me) give any value close to the real ones? I feel like I'm really missing something.

Can someone shed some light on this?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Zeeman effect, something I'm not understanding, about history

**Physics Forums | Science Articles, Homework Help, Discussion**