PRERESONANCE HYPER-RAMAN SCATTERING STUDIES OF ETHYLENE-GLYCOL

The first reported experimental example of clearly preresonant hyper-R aman scattering is presented. The preresonance hyper-Raman spectrum of liquid ethylene glycol is obtained with 426 nm excitation and compare d with the corresponding preresonance Raman spectrum. The spectra are analyzed in terms of the conventional vibronic expansion, and it is sh own that, by comparing peak heights in the Raman and hyper-Raman spect ra, the relative magnitude of one- and two-photon dipole transition mo ments of contributing electronic states may be determined. Tentative s ymmetry assignments for contributing states are also discussed. The re sults demonstrate the applicability of preresonance hyper-Raman scatte ring when studying electronic transitions in the VUV.