  We study the directional dichroic absorption spectra in the x-ray region in a
polar ferrimagnet GaFeO_3. The directional dichroism on the absorption spectra
at the Fe pre-K-edge arises from the E1-E2 interference process through the
hybridization between the 4p and 3d states in the noncentrosymmetric
environment of Fe atoms. We perform a microscopic calculation of the spectra on
a model of FeO_6 with reasonable parameter values for Coulomb interaction and
hybridizations. We obtain the difference in the absorption coefficients when
the magnetic field is applied parallel and antiparallel to the c axis. The
spectra shus obtained have similar shapes to the experimental curves as a
function of photon energy in the Fe pre-K-edge region, although they have
opposite signs.
