Look in Cowan: The theory of atomic structure and spectra p485-498

The slope in the energy vs. field plot is related to the g-factor, Bohr-magnetron and magnetic quantum number of the state. 

Dear Dinesh:

The Landé g-factor is related to the energy levels in an atom under a weak magnetic field. The quantum states of electrons in atomic orbitals are degenerates in energy, with these degenerated states sharing the same angular momentum.

Regards,

Antonio

Look in Cowan: The theory of atomic structure and spectra p485-498

The slope in the energy vs. field plot is related to the g-factor, Bohr-magnetron and magnetic quantum number of the state. 

An electron with a magnetic moment will experience a torque when it is put in a magnetic field. Now where will this magnetic moment originate? Both orbital and spin angular momentum will contribute to its magnetic moment.

μL= - (e/2m) ⃗L and μS= - g (e/2m) ⃗S

Here g is the Lande g factor. For electron g=2. The physical significance is that spin angular momentum of electron is twice as effective in producing magnetic moment.

For muons the measured value of g may differ slightly from 2 by loop effects produced by new physics effects beyond the standard model. This difference is not solely due to the fact that mass of muon is different from mass of the electron, which would be one's naive expectation.  For example in MSSM a triangle diagram involving neutralino and smuon will contribute to muon g-2.   For experimental searches of muon g-2 see:

http://muon-g-2.fnal.gov/

g-factor (also called g value or dimensionless magnetic moment) is a dimensionless quantity that characterizes the magnetic moment and angular momentum of an atom, a particle or nucleus.