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Proceedings Paper

Raman excitation profile of nitrobenzene: prospect of Raman lidar detection
Author(s): Sheikh Rafi Ahmad; V. G. Foster
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Paper Abstract

The absolute values of the Raman scattering cross-section of the 1347 cm-1 NO2 symmetric stretch mode of nitrobenzene vapor were measured at some discrete excitation wavelengths in the range 240 nm to 420 nm. An analytical expression for their wavelength dependence was obtained from the numerical `best fit' of the data to Albrecht `A' term. The Raman excitation profile, thus created, exhibits a strong resonance effect, attributed to the charge-transfer state in C6H5NO2 corresponding to the absorption peak at 240 nm. At near resonance excitation (250 nm) the Raman cross-section was found to be more than two orders of magnitude higher than that expected at the same wavelength from (lambda) -4 dependence. Although the excitation profile remained the same, the vapor phase cross-section values were almost an order of magnitude lower than those measured in liquid phase. The implication of resonance enhancement on the Raman lidar detection of NB vapor was analyzed for a standard atmospheric model with different ozone loadings using LOWTRAN7 computer code.

Paper Details

Date Published: 12 November 1996
PDF: 10 pages
Proc. SPIE 2833, Application of Lidar to Current Atmospheric Topics, (12 November 1996); doi: 10.1117/12.258145
Show Author Affiliations
Sheikh Rafi Ahmad, Royal Military College of Science/Cranfield Univ. (United Kingdom)
V. G. Foster, Royal Military College of Science/Cranfield Univ. (United Kingdom)


Published in SPIE Proceedings Vol. 2833:
Application of Lidar to Current Atmospheric Topics
Arthur J. Sedlacek, Editor(s)

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