AbstractThe Raman spectra of solid complexes formed between halogens as electron donors and benzene and methylated benzenes as electron acceptors were measured at 77 K. Great increase in intensity was observed for the Raman lines ν10(e1g), ν16(e2u) and ν17(e2u) of benzene on complex formation. The great intensity enhancement of these out‐of‐plane bending modes is reasonably explained as the result of mixing of the1A2u(σπ*) state of benzene and the charge transfer state. The observed spectra are consistent with the crystal structure of factor groupC3ν, having one halogen molecule and one benzene molecule in a unit cell, which was proposed by Personet al.from the infrared spectra. It was found that the Raman spectra of the complexes provide a good test for the Raman intensity mechanism proposed for benzene and also give important information about electronic excited states which are not identifiable by ot