IR OVERTONE REGION FOR THE OUT-OF-PLANE WAGS OF BICYCLIC AROMATIC COMPOUNDS: CLUES TO HIDDEN FUNDAMENTALS

Work supported by the Department of Energy (Office of Basic Energy Science)Author Institution: National Institute for Petroleum and Energy ResearchThe region from 2000 to $1650 cm^{-1}$ in the infrared vapor spectrum for indole and related compounds exhibits several transitions, none of which are due to fundamentals. Careful analysis shows that nearly all of these should be assigned to overtones/combinations of the out-of-plane wags of the hydrogen groups. In a few cases, the fundamental itself is not observable in the infrared vapor spectrum due to low transition strength. The results help to pinpoint the location of these particular fundamentals and give an indication of the amount of anharmonicity as well. The complete set of wag frequencies for these molecules are shown to correspond quite closely to those of the respective monocyclic species