However, it does not capture the intensity of the CH stretch around 3000 cm -1 . On the other hand, a second isomer (B) which is higher in energy, does capture the CH and CO stretches well. Given the prominent OH stretch and anomalously intense CH stretching feature, we suggest that we are observing an isomeric mixture of these two structures. Additional isomers similar to A were computed, in which the double bond was permuted around the ring, but none produced qualitatively different spectra and were significantly higher in energy (Figure ).