Theoretical calculations of low-frequency spectra, due to intermolecular collective modes in liquid benzene, are presented. The molecules in a liquid are assumed to be organized in instantaneous, quasicrystalline, short-range structures of the lifetime of order of 10(-13) s, which perform rotational and translational vibrations. Those vibrations are responsible for the intermolecular part of the femtosecond optical Kerr effect response. The spectra, obtained for five different temperatures, show a good agreement with the experimental results of other authors. We prove that the low-frequency feature of the spectrum, which is evidently augmented at low temperatures, is associated with collective translational intermolecular vibrations.