Abstract

Preparing highly vibrationally excited molecules by vibrational-overtone excitation and probing them or their reaction products spectroscopically provides new information on the interaction of high- and low-frequency modes. We use three different approaches in which we probe the excited molecule by laser-induced fluorescence, by monitoring unimolecular reaction products spectroscopically, or by photodissociating the vibrationally excited molecule and probing the dissociation products spectroscopically. The "action" spectra coming from these measurements show the influence that the excitation of stretching vibrations has on other vibrations in the molecule. One example is the interaction of the O-H stretching vibration with the torsion in hydroperoxides (HOOX), such as hydrogen peroxide (x = H) and t-butyl-hydroperoxide (x = t - bu). Our analysis shows that the height of the lower barrier in the double-minimum potential of these molecules increases with increasing-O-H stretching excitation.

© 1990 Optical Society of America