Question

a) For the zeeman effect what is generally the shape of the magnetic field between the pole pieces of the electromagnets and what effect might the shape of the magnetic field have on the results of this experiment?
b) How would the interference pattern observed for the normal Zeeman effect (eg with a cadmium lamp) differ from the anomalous Zeeman effect transition?

Answer 1

a) The magnetic field is inhomogeneous such that at a certain point in z direction it varies strongly with z so that the atoms are acted upon by a force in z direction only. If the magntic field is not inhomogeneous then the net force on the atoms will be zero and hence no splitting of spectral lines is observed. A typical setup is shown below (source: google image)

b) In normal Zeeman effect the net spin angular momentum is zero. So only pure orbital angular mometum is responsible for the splitting of spectral lines. Hence a state with angular momentum l will be split into (2l+1) states whereas in anomalous Zeeman effect both the spin angular momentum and orbital angular momentum are responsible for splitting of spectral lines as net spin angular momentum S is not zero as well as net orbital angular momentum is also non zero. So in this case a state with total angular momentum J is split into (2j+1) states.