The studies of reorientational motions of molecules in crystals
of organic compounds by low-frequency Raman spectroscopy are
briefly reported. Some examples illustrate the efficiency of the
investigation of order-disorder phenomena in organic crystals by
the temperature dependence of low-frequency vibrational spectra
combined with simultaneous calculations of the molecular dynamics
by the atom-atom potentials (AAP) method. The conditions have been determined which are necessary in order to affect the low-frequency Raman spectra by anisotropy of molecular reorientations in crystals