Several orders of magnitude enhancements in the rate constants for three slow ion-molecule reactions with Hz have been observed when the H2 is vibrationally excited. The atomic cations C+, He+, and Ne+ were all observed to react near their respective Langevin rates with vibrationally excited HZ.
Semiclassical variational transition state calculations for the reactions of H and D with thermal and vibrationally excited H2
β Scribed by Bruce C. Garrett; Donald G. Truhlar; A. J. C. Varandas; Normand C. Blais
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 651 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0538-8066
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β¦ Synopsis
We present calculations of the rate constants for the title reactions on a new accurate potential energy surface with a 9.65 kcal mol-barrier and a carefully fitted long-range attraction. The low-temperature thermal rate constant decreases from the previously calculated value, corresponding to a surface with a barrier of 9.80 kcal mol-', which is opposite to the direction of change expected because of the change in barrier height. This demonstrates the sensitivity of tunneling contributions to more global characteristics of the surface. The excited-state ( n = 1) rate constants also change slightly, but not nearly enough to settle the controversial disagreement of theory with experiment for these rate constants.
used for these comparisons was the analytic representation of the
π SIMILAR VOLUMES
Coupled ~schar~flow system, T. 0. F. mass spectrometer observations of the mass 2 peak in the active Hz/C12 system showed unexpected consumption of some hydrogen. This fs suggested tc arise from the reaction C1+ tl~ --) HCl i Cl. enhanced in rate by H2 vibrational excitation. Evidence far similar pa
Ck~sical trajectory cakuk~tions for the collinea\_r H+H2 exchange reaction weie performed QSiIIg the same poten-. ## I&J merg surface pretiou+ly adopted for exact quantum mechanical calculationr Reactions of bath sound state amjv-ibrationdy excited aate reagent were wwidered, over a relative kine
A sudden IransiIion state theory IS used LO show that Ihe recenl ab initio computarlons or Fnsch. Bmhley and Schaerer or the saddle poim properries of the FH 2 system are compatible uilh thermal rale and molecular beam expcrimcnw
The accuracy of the SAC-Cl (symmetry-adapted-cluster configuration-interaction) method is examined for the singlet and triplet excited states of Hz0 by comparison with the full-Cl results for the [4s2p] basis set. The SAC-C1 results for the excitation energy agree with the full-Cl results to within