Table of Contents
Laser Chemistry
Volume 10, Issue 5-6, Pages 377-388

Angular Selection of Products by Use of Saturated-Absorption Techniques in the Cs(7P)+H2CsH+H Reaction

Laboratoire Aimé Cotton, C.N.R.S. II Bat. 505, Orsay-Cedex 91405, France

Received 20 February 1990; Accepted 1 March 1990

Copyright © 1990 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.


The Cs(7P)+H2CsH+H reaction is studied in a crossed-beam experiment with laser-induced fluorescence detection of CsH products. The usual flux (50mW/mm2) which is delivered by the C.W. tunable dye laser used in the experiment is enough to saturate the absorption by CsH products. Then, by crossing twice the laser beam through the collision volume (counterpropagating beams), one realizes the conditions of saturated-absorption experiments: when the laser frequency is tuned to a resonance frequency of CsH products, a defect to absorption occurs for these products which scatter in the collision plane and a "saturation dip" appears at the center of the corresponding fluorescence profile. Application of this technique to crossed-beam experiments can lead to the selection of product molecules which scatter in any definite plane. A different geometry of the laser beams (bent beams) is proposed to select molecules which scatter in any definite direction: it could be applied to detect an asymmetry in the scattering of the products with respect to the collision axis, when a particular preparation of the reagents is realized.