Question

Selection rule for pure rotational raman spectra of diatomic molecules

Answer 1

Raman spectra. For Raman spectra the molecules undergo transitions in which an incident photon is absorbed and another scattered photon is emitted. ... The selection rule for linear molecules is ΔJ = 0, ±2. The reason for the values ±2 is that the polarizability returns to the same value twice during a rotation.