small hump appears at the low energy side. Difference is the magnitude of the intensity. Figure \[fig.parameter\](b) shows the main-peak intensity as a function of $|E_f|/D_f$. It increases with increasing values of $|E_f|/D_f$. In the same figure, we have also plotted the sublattice quadrupole moment as a function of $|E_{f}|/D_{f}$. It also increases with increasing values of $|E_{f}|/D_{f}$. This coincidence is plausible, since the charge anisotropy in the $4f$ states increases with increasing the ordered quadrupole moment. However, its magnitude remains much smaller than those given by the direct influence of lattice distortion in a wide parameter range of crystal field by comparison with the curve in Fig. \[fig.parameter\](a).

Concluding Remarks
==================

We have studied the mechanism of RXS at the $L_{\rm III}$ edge in the quadrupole ordering phase of DyB$_2$C$_2$. Having analyzed the effect of the bucking of sheets of B and C atoms on the $5d$ and $4f$ states, we have constructed an effective model that the crystal field is acting on the $5d$ and $4f$ states with the principal axes different for different sublattices. We have calculated the RXS spectra in the $E_1$ process by treating the $5d$ states as a band and the $4f$ states as 