| Autor: |
Nisalak Trongsiriwat, Tolga N. V. Karsili, Guanghan Wang, Michael F. Vansco, Adriana Caracciolo, Patrick J. Walsh, Barbara Marchetti, Marsha I. Lester, Tianlin Liu |
| Rok vydání: |
2021 |
| Předmět: |
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| Zdroj: |
The Journal of chemical physics. 155(17) |
| ISSN: |
1089-7690 |
| Popis: |
The electronic spectrum of methyl vinyl ketone oxide (MVK-oxide), a four-carbon Criegee intermediate derived from isoprene ozonolysis, is examined on its second π* ← π transition, involving primarily the vinyl group, at UV wavelengths (λ) below 300 nm. A broad and unstructured spectrum is obtained by a UV-induced ground state depletion method with photoionization detection on the parent mass (m/z 86). Electronic excitation of MVK-oxide results in dissociation to O (1D) products that are characterized using velocity map imaging. Electronic excitation of MVK-oxide on the first π* ← π transition associated primarily with the carbonyl oxide group at λ > 300 nm results in a prompt dissociation and yields broad total kinetic energy release (TKER) and anisotropic angular distributions for the O (1D) + methyl vinyl ketone products. By contrast, electronic excitation at λ ≤ 300 nm results in bimodal TKER and angular distributions, indicating two distinct dissociation pathways to O (1D) products. One pathway is analogous to that at λ > 300 nm, while the second pathway results in very low TKER and isotropic angular distributions indicative of internal conversion to the ground electronic state and statistical unimolecular dissociation. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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