We analyse an effect of electron Fermi motion at atomic shells on the accuracy of electron beam polarization measurements with a M\"oller polarimeter operating in a double--arm mode. It is demonstrated that the effect can result in either {\it increase} or {\it decrease} of the measured polarization depending on the detector positions. The effect is simulated for the M\"oller polarimeter to be installed at CEBAF Hall A.
@article{arxiv.hep-ex/9602002,
title = {Atomic Electron Motion for M\"oller Polarimetry in a Double-Arm Mode},
author = {Andrei Afanasev and Alexander Glamazdin},
journal= {arXiv preprint arXiv:hep-ex/9602002},
year = {2007}
}