Solvation Ultrafast Dynamics of Reactions. 13. Theoretical and Experimental Studies of Wave Packet Reaction Coherence and Its Density Dependence
- Creators
- Liu, Qianli
- Wan, Chaozhi
- Zewail, Ahmed H.
Abstract
In this paper of the series, which gives the full account of an earlier communication [Liu et al. J. Chem. Phys. 1996, 105, 5294], the reaction wave packet coherence of iodine in rare-gas fluids is studied, both experimentally and theoretically, in the gas-to-liquid transition region. The phase coherence dynamics, which exhibit striking density behavior, are resolved in real time and across a broad density range (0−35 nm^(-3)) for three different rare gases: helium, neon, and argon. In the solvent, the wave packet reaction coherence is observed on time scales longer than that of the solute vibrational motion, and the loss of coherence is due to solvent collision-induced predissociation and collision-induced dephasing. By means of molecular dynamics simulations, the experimental results are reproduced by classical and semiclassical treatments. The centrifugal force, by vibration−rotation coupling, is found to be dominant at low and intermediate densities. A motion narrowing effect causes the contribution of vibration−rotation coupling to dephasing to decrease at high densities. Direct contributions from the solute−solvent forces increase with the solvent density throughout the whole dynamics range. The combining influence of the two forces gives rise to the drastically different behaviors observed in three different density regions.
Additional Information
© 1996 American Chemical Society. Received: August 9, 1996; In Final Form: September 23, 1996. Publication Date (Web): November 28, 1996. This research was supported by the National Science Foundation. Most of the simulation works were performed on the Delta parallel supercomputer of Caltech. We thank the Center for Advanced Computer Research (CACR) for providing us with the access to its computational resources. We also thank Mr. Manish Gupta for his efforts in the initial stage of the research and for all his help.Additional details
- Eprint ID
- 69879
- DOI
- 10.1021/jp962432v
- Resolver ID
- CaltechAUTHORS:20160824-074504807
- NSF
- Created
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2016-08-26Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field