Zeeman effect

[Rajini]

Hello all,

I am confused with naming of the Zeeman effect (in nuclear or/and electronic levels).

Is that means:
1. splitting of spectral lines due to internal magnetic field,
or
2. splitting of spectral lines due to external magnetic field,
or
3. splitting of spectral lines due to static magnetic field.

Which is the correct one. Because many website use all the three..I guess some historical reason should be the cause.

thanks

[Naty1]

Try reading here:
http://en.wikipedia.org/wiki/Zeeman_effect

particularly the weak field discussion.