Ultrafast photodissociation studies of acetyl cyanide and acetic acid and unimolecular decomposition rates of the acetyl radical products
| Autor: | Jeffrey C. Owrutsky, Andrew P. Baronavski |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
education.field_of_study
Chemistry Population Photodissociation Ab initio General Physics and Astronomy Acetyl cyanide Photoionization Photochemistry Acetic acid chemistry.chemical_compound Computational chemistry Excited state Physics::Chemical Physics Physical and Theoretical Chemistry education Spectroscopy |
| Zdroj: | The Journal of Chemical Physics. 111:7329-7336 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.480056 |
| Popis: | Unimolecular decomposition rates for acetyl radical following the photodissociation of acetyl cyanide and acetic acid near 193 nm have been studied using ultrafast mass-resolved photoionization spectroscopy. In both cases, the parent decays with an instrumentally limited lifetime, while the acetyl radical behaves in a manner consistent with an RRKM mechanism, in contrast to our previous results on acetone. It is necessary to convolute the population distribution with the microcanonical RRKM rates in order to achieve this agreement. We have also undertaken an ab initio study of the excited states of acetyl cyanide to clarify the assignments of these states. The state excited at 193 nm arises from a π→π* transition with a calculated transition velocity dipole moment oriented at an angle of 57° with respect to the C–C≡N bond, resulting in an anisotropy parameter of −0.22. This is in reasonable agreement with the previous data of North et al. [J. Phys. Chem. A 101, 9224 (1997)]. The apparent RRKM behavior of ... |
| Databáze: | OpenAIRE |
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