VIBRATIONAL OVERTONE SPECTROSCOPY OF CYCLOHEPTATRIENE

The spectrum of the first through fifth vibrational overtone absorptio ns of cycloheptatriene is reported. The spectrum for the first and sec ond overtones was recorded using a liquid sample, while the third, fou rth, and fifth overtones were recorded for gaseous samples. A method i s developed using the correlation between ab initio CH bond lengths an d the local mode transition energy to predict the experimental spectra for the third, fourth, and fifth vibrational overtone spectra. These predictions were used to assign the absorption peaks for the ''boat'' conformer of cycloheptatriene in the gaseous spectrum. Progressions be longing to the olefinic and methylenic CH bond stretches are identifie d for both the gaseous and liquid data.