The Raman spectra of sulphur and phosphorus - Part II. Lattice oscillations
The existing theories regarding the origin of the discrete Raman lines in the solids in the place of the wings accompanying the Rayleigh line in liquids are reviewed. An intense sharp line at 36 cm.−1 has been reported for solid phosphorus which broadens to a depolarised wing in the liquid state. This frequency agrees well with the frequency of vibration of the crystal lattice calculated from the melting point of phosphorus and therefore, owes its origin to the latter. The Raman line at 88 cm.−1 observed for rhombic sulphur appears as a weak diffuse depolarised line in liquid sulphur at 80 cm.−1 and is also attributed to lattice vibrations. The objections for assigning these lines either to Pauling rotation or to intermolecular oscillations of polymerised groups are indicated.