Table of Contents
Laser Chemistry
Volume 15, Issue 1, Pages 1-19
http://dx.doi.org/10.1155/1994/74032

Radiative Lifetimes and Collision Processes in Sodium-Rare Gas and Sodium-Hydrogen Systems

1Department of Mechanical Engineering, Loughborough University of Technology, Loughborough, Leics., LE11 3TU, UK
2Department of Physics, University College of Wales, Swansea, Singleton Park., Wales., SA2 8PP., UK

Received 8 March 1993

Copyright © 1994 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

Investigations of the collisional interactions between sodium atoms in the 32P states and helium and hydrogen gases are described. Studies of collision-induced mixing and quenching interactions have been carried out under conditions where chemical reaction to produce sodium hydride is possible. Thus the sodium number derivatives are sufficient for radiation trapping to occur. This is in contrast to virtually all previous investigations in which conditions were such that this effect need not be considered. The intensity and temporal behaviour of laser induced fluorescence (LIF) resulting from the photoexcitation of the sodium 32P states is monitored as a function of foreign gas pressure. Whilst many of the features observed are to be expected, results show how radiation trapping strongly influences cross-section determination. The need for a more rigorous treatment of collision cross-sections under these conditions, which are often more realistic than the ‘ideal’ trapping free situations, is demonstrated.