  The atomic ionization processes induced by scattering of neutrinos play key
roles in the experimental searches for a neutrino magnetic moment. Current
experiments with reactor (anti)neutrinos employ germanium detectors having
energy threshold comparable to typical binding energies of atomic electrons,
which fact must be taken into account in the interpretation of the data. Our
theoretical analysis shows that the so-called stepping approximation to the
neutrino-impact ionization is well applicable for the lowest bound Coulomb
states, and it becomes exact in the semiclassical limit. Numerical evidence is
presented using the Thomas-Fermi model for the germanium atom.
