Table of Contents
Laser Chemistry
Volume 19, Issue 1-4, Pages 335-341
http://dx.doi.org/10.1155/1999/21312

Picosecond Anti-Stokes Raman Excitation Profiles as a Method for Investigating Vibrationally Excited Transients

1Research Centre for Spectrochemistry, Department of Chemistry, School of Science, The University of Tokyo, Bunkyo-ku 113, Tokyo, Japan
2Department of Chemistry, Faculty of Science University, Saitama University, Urawa 338, Saitama, Japan

Received 7 April 1997

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A method for estimating vibrational quantum numbers of vibrationally excited transients in solution is proposed. In this method, we calculate anti-Stokes Raman excitation profiles (REPs) which are characteristic of the initial vibrational states involved in the Raman process, and compare them with observed anti-Stokes intensities. We have applied this method to vibrationally hot molecules of canthaxanthin in the So state and those of trans-stilbene in the S1 state. For canthaxanthin, it has been found that the vibrationally excited transients are for the most part on the ν=1 level of the C═C stretching mode, and that excess vibrational energy is statistically distributed among all intramolecular vibrational modes. As for S1 stilbene, vibrational transients are shown to be mostly on the ν=1 level for two vibrational modes examined, while the excess vibrational energy is probably localised on the olefinic C═C stretching mode.