ANOMALOUS BEHAVIOR OF O-18-LABELLED COMPOUNDS .16. RELATIVE INTEGRATED INTENSITY OF THE MAIN O-18-SENSITIVE RAMAN BANDS OF MONOMERIC O-18-LABELLED BENZOIC-ACID

The 20-3500 cm-1 Raman spectrum of a dilute CH2Cl2 solution of 92.9 atom% 18O-benzoic acid was compared with the corresponding spectrum of a similar solution of normal benzoic acid. The observed bands were assigned to their original modes of vibration. The relative integrated intensity of the 18O-sensitive bands of normal benzoic acid observed thus at 414, 790 and 1644 cm-1 was compared with the respective intensity of the corresponding 18O-benzoic acid bands at 400, 774 and 1628 cm-1. The latter intensity was found to be in each case 30-50% less than the former one. © 1979.