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Real-time dynamics of clusters. III. I2Nen (n=2–4), picosecond fragmentation, and evaporation

Gutmann, M. and Willberg, D. M. and Zewail, A. H. (1992) Real-time dynamics of clusters. III. I2Nen (n=2–4), picosecond fragmentation, and evaporation. Journal of Chemical Physics, 97 (11). pp. 8048-8059. ISSN 0021-9606. http://resolver.caltech.edu/CaltechAUTHORS:GUTjcp92b

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Abstract

In this paper (III) we report real-time studies of the picosecond dynamics of iodine in Ne clusters I<sup>*</sup><sub>2</sub>Nen(n = 2–4) --> I<sup>*</sup><sub>2</sub> + nNe. The results are discussed in relation to vibrational predissociation (VP), basic to the I2X systems, and to the onset of intramolecular vibrational-energy redistribution (IVR). The latter process, which is a precursor for the evaporation of the host atoms or for further fragmentation, is found to be increasingly effective as the cluster size increases; low-energy van der Waals modes act as the accepting (bath) modes. The reaction dynamics for I2Ne2 are examined and quantitatively compared to a simple model which describes the dynamics as consecutive bond breaking. On this basis, it is concluded that the onset of energy redistribution is observed in I2Ne2. Comparison of I2Ne and I2Ne2 to larger clusters (n=3,4) is accomplished by introducing an overall effective reaction rate. From measurements of the rates and their dependence on v<sup>[script ']</sup><sub>i</sub>, the initial quantum number of the I2 stretch, we are able to examine the dynamics of direct fragmentation and evaporation, and compare with theory.


Item Type:Article
Additional Information:Copyright © 1992 American Institute of Physics (Received 1 July 1992; accepted 25 August 1992) Note added in proof. Studies of the elementary nuclear motion on the femtosecond time scale has been reported recently for iodine in large argon clusters.[37] This work was supported by a grant from the National Science Foundation (DMR). [M.G. was a] Deutsche Forschungsgemeinschaft post-doctoral fellow from Germany. Arthur Amos Noyes Laboratory of Chemical Physics, Contribution No. 8639.
Subject Keywords:MOLECULAR CLUSTERS; IODINE COMPLEXES; NEON COMPLEXES; VIBRATIONAL STATES; PREDISSOCIATION; PS RANGE; PRECURSOR; SIZE; SYMMETRY BREAKING; CHEMICAL BONDS; QUANTUM NUMBERS; EVAPORATION; VAN DER WAALS FORCES
Record Number:CaltechAUTHORS:GUTjcp92b
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:GUTjcp92b
Alternative URL:http://dx.doi.org/10.1063/1.463427
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5412
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:16 Oct 2006
Last Modified:26 Dec 2012 09:05

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