Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 22 June 2007:
Vol. 316. no. 5832, pp. 1723 - 1726
DOI: 10.1126/science.1142313
Prev | Table of Contents | Next

Reports

Do Vibrational Excitations of CHD3 Preferentially Promote Reactivity Toward the Chlorine Atom?

Shannon Yan,1 Yen-Tien Wu,1 Bailin Zhang,1* Xian-Fang Yue,1{dagger} Kopin Liu1,2{ddagger}

The influence of vibrational excitation on chemical reaction dynamics is well understood in triatomic reactions, but the multiple modes in larger systems complicate efforts toward the validation of a predictive framework. Although recent experiments support selective vibrational enhancements of reactivities, such studies generally do not properly account for the differing amounts of total energy deposited by the excitation of different modes. By precise tuning of translational energies, we measured the relative efficiencies of vibration and translation in promoting the gas-phase reaction of CHD3 with the Cl atom to form HCl and CD3. Unexpectedly, we observed that C–H stretch excitation is no more effective than an equivalent amount of translational energy in raising the overall reaction efficiency; CD3 bend excitation is only slightly more effective. However, vibrational excitation does have a strong impact on product state and angular distributions, with C–H stretch-excited reactants leading to predominantly forward-scattered, vibrationally excited HCl.

1 Institute of Atomic and Molecular Sciences, Academia Sinica, Post Office Box 23-166, Taipei, Taiwan 10617.
2 Department of Chemistry, National Taiwan University, Taipei, Taiwan 10617.

* Present address: Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.

{dagger} Present address: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.

{ddagger} To whom correspondence should be addressed. E-mail: kliu{at}po.iams.sinica.edu.tw

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
CH Stretching Excitation in the Early Barrier F + CHD3 Reaction Inhibits CH Bond Cleavage.
W. Zhang, H. Kawamata, and K. Liu (2009)
Science 325, 303-306
   Abstract »    Full Text »    PDF »
Chemical Dynamics Special Feature: Tracking the energy flow along the reaction path.
S. Yan, Y.-T. Wu, and K. Liu (2008)
PNAS 105, 12667-12672
   Abstract »    Full Text »    PDF »
Chemical Dynamics Special Feature: Vibrational vs. translational energy in promoting a prototype metal-hydrocarbon insertion reaction.
D. L. Proctor and H. F. Davis (2008)
PNAS 105, 12673-12677
   Abstract »    Full Text »    PDF »
Chemical Dynamics Special Feature: Chemical dynamics of vibrationally excited molecules: Controlling reactions in gases and on surfaces.
F. F. Crim (2008)
PNAS 105, 12654-12661
   Abstract »    Full Text »    PDF »
Bond-Selective Control of a Heterogeneously Catalyzed Reaction.
D. R. Killelea, V. L. Campbell, N. S. Shuman, and A. L. Utz (2008)
Science 319, 790-793
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)