The Drude model relates the macroscopic susceptibility to the microscopic quantities carrier concentration n and mobility μ:

e is the charge and m the effective mass of the charge carriers. The damping constant Ωτ and ΩP (which is called plasma frequency), are the two fit parameters of the model. Both are given in wavenumbers. Alternatively one can also compute the resistivity:

 .

For p-doped silicon the effective mass is 0.37 times the electron mass which leads to the following simpler versions of the relations given above:

These relations will be used to convert the fit parameters to the wanted carrier properties.