In an ionic crystal (like NaCl, CaF2, etc.) one has to take into account infra-red resonan...

In an ionic crystal (like NaCl, CaF2, etc.) one has to take into account infra-red resonance oscillations of the ions. Show that Eq. (68) modifies to

where M represents the reduced mass of the two ions and p represents the valency of the ion (p = 1 for Na+, Cl –; p = 2 for Ca++, F2– –). Show that the above equation can be written in the form*

where