Table of Contents
Laser Chemistry
Volume 15, Issue 2-4, Pages 145-156

Competition Between Intramolecular Vibrational Energy Re-Distribution and Unimolecular Dissociation: A Scattering Theoretical Point of View

1Division of Theoretical Studies, Institute for Molecular Science, Myodaiji, Okazaki 444, Japan
2Molecular Physics Division, National Institute of Standards and Technology, Gaithersburg 20899, Maryland, USA

Received 15 March 1994

Copyright © 1995 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.


Systematic behavior of decay rates of resonances above dissociation threshold is investigated by using the theory of resonance scattering. The condition for the Rice-Ramsperger-Kassel-Marcus (RRKM) rate formula to be valid is clarified by analyzing the random model of unimolecular dissociation. The decay rate averaged over many resonances agrees with the RRKM rate when the mean spacing and the mean width of the resonance states coincide with each other. On the other hand, auto- and mutual-correlation functions of the non-stationary wave functions indicate a rather paradoxical and intriguing phenomenon: In the RRKM regime, insufficient time is left for intramolecular vibrational energy redistribution (IVR) before dissociation.