Resonance Raman effect of anthracene in the pre-resonance region

The Raman intensities (RI) of ten vibrations of Anthracene have been measured as a function of the excitation frequency using nine lines from an argon ion and a krypton ion laser. The intensities taken relative to those for a particular excitation frequency, S/S (v0), do not show uniform resonance behaviour. However uniformity arises, when the relative intensities are expressed on the same scale, and such ΔS/ΔS0 values may reflect the influence of frequency factors and varying percentage π‐dependence.