Multiphonon absorption bands in MgO

Abstract Lattice bands in MgO involving interactions of infrared radiation with one, two, three, four and five phonons have been observed between 300 to 2000 cm −1 . These multiphonon combination bands (summation or difference) have been explained in terms of four characteristic phonons (LO, TO, LA and TA) at or near the zone boundary. Two-phonon difference bands have also been observed towards the lower frequency, ( c ), side of the spectrum.