Second-Order Raman Spectrum of MgO

The second-order Raman spectrum of MgO at room temperature is reported for different polarizations and crystal orientations. The parts of the scattering polarizability transforming as $A_{1g}$, $E_g$, and $T_{2g}$ are separated and compared with features in the two-phonon dispersion curves at the critical points $\Gamma$, $X$, $L$, and $W$.