  Electron polarimeters based on Mott scattering are extensively used in
different fields in physics such as atomic, nuclear or particle physics. This
is because spin-dependent measurements gives additional information on the
physical processes under study. The main quantity that needs to be understood
in very much detail, both experimentally and theoretically, is the
spin-polarization function, so called analyzing power or Sherman function. A
detailed theoretical analysis on all the contributions to the effective
interaction potential that are relevant at the typical electron beam energies
and angles commonly used in the calibration of the experimental apparatus is
presented. The main contribution leading the theoretical error on the Sherman
function is found to correspond to radiative corrections that have been
qualitatively estimated to be below the 0.5% for the considered kinematical
conditions: unpolarized electron beams of few MeV elastically scattered from a
gold and silver targets at backward angles.
