QUANTITATIVE STUDY OF EXCITATION PROFILES OF TOTALLY SYMMETRIC AND NONTOTALLY SYMMETRIC VIBRATIONS OP PYRAZINE WITH TUNABLE UV LASERS--A CRITICAL EXAMINATION OF VARIOUS THEORIES OF RAMAN INTENSITIES
Publisher:
Ohio State UniversityAbstract:
The resonant Raman effect of pyrazine was studied quantitatively with tunable UV lasers at liquid helium temperature. Solid solutions of pyrazine in benzene with various concentrations (3% to 0.1%) were used. Using the 990 $cm^{-1}$ benzene vibration as reference, the excitation profiles of Raman intensities for $\nu _{1}, \nu_{9}, \nu_{6a},$ and $\nu _{10a}$ were determined. It was found that both $\nu_{6a}$ and $\nu_{10a}$ are enhanced by a factor of $10^{6}$. The functional dependence is quite different for different vibrations, e.g., $\nu _{6a}$ shows a $(\Delta E)^{-2}$ dependence $(\Delta E $ is the difference between the excitation energy and the resonance), whereas, $\nu_{10a}$ shows a $(\Delta E)^{-4}$ dependence off resonance and a $(\Delta E)^{-1}$ dependence near resonance. Existing theories by Albrecht, Peticolas, etc., would predict $(\Delta E)^{-4}$ off resonance and $(\Delta E)^{-2}$ near resonance for $\nu_{10a}$ and $(\Delta E)^{-4}$ for $\nu_{6a}$ throughout.
Description:
Author Institution: Radiation Laboratory University of Notre Dame
Type:
articleOther Identifiers:
1977-FA-6Items in Knowledge Bank are protected by copyright, with all rights reserved, unless otherwise indicated.