[en] Recent theoretical studies of coherent propagation effects in SF₆ and other polyatomic molecules are summarized beginning with an account of relevant aspects of the high-resolution spectroscopy of the ν₃ band of SF₆. A laser pulse propagating in a molecular gas can acquire new frequencies which were not initially present in the pulse, and, in fact, a wave is coherently generated at the frequency of every molecular transition accessible from the initial molecular energy levels. The possible consequences of coherent generation of sidebands for the multiple-photon excitation of SF₆ and other polyatomic molecules are discussed