Second order Raman spectrum of carbon disulphide in the condensed phase

Below 162K, carbon disulphide crystallizes in the space group D 2h 18 with two molecules in the primitive cell. The internal modes v 1 , v 2 and v 3 of the isolated CS 2 molecule are split due to static and correlation field splittings. Anderson et al . have extensively studied the Raman and infrared spectra of CS 2 at 79 K and 18 K and have analysed the internal and external modes with a lattice dynamical calculation of the q = 0 phonons. However, their spectra reveal the presence of extensive second order features accompanying the v 1 , v 2 , v 3 and 2 v 1 bands. The present investigation attempts an interpretation of these second order Raman spectra employing Born's theory and the lattice dynamical calculation of phonons at all allowed q points in the Brillouin zone employing the rigid molecule approximation.