RAMAN AND ELECTRONIC SPECTRA OF TRANSIENT MOLECULES BY NONLINEAR THREE WAVE MIXING IN GASES
Loading...
Date
1978
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Applications of nonlinear three wave mixing spectroscopy in the study of transient species will be described. In these experiments, excited molecular states and/or photofragments are produced by laser excitation at 266 or 355 nm. Simultaneous or delayed laser probe beams ($\omega_{1}$ and $\omega_{2}$) sample the photolysis focal volume and $\omega_{2}$ is tuned to generate a coherent anti-Stokes signal beam at $\omega_{3} = 2\omega_{1} - \omega_{2}$. Depending on the system, either vibrational (CARS) or electronic spectra are obtained. It will be shown that the latter is the case for photofragments of benzene and related molecules. Although benzene does not absorb appreciably at 266 nm, the near one photon resonance with the lowest singlet state at 263 nm leads to efficient two photon photolysis at 133 nm. The large $\omega_{3}$ signals of the products suggest that resonance enhancement is also occurring in the three wave mixing process in the photofragments. Identification of the fragments and the Interpretation of the spectra will be considered.
Description
Author Institution: Department of Chemistry, Oregon State University