Details

Autor(en) / Beteiligte

• Wang, Guanghan
• Liu, Tianlin
• Caracciolo, Adriana
• Vansco, Michael F.
• Trongsiriwat, Nisalak
• Walsh, Patrick J.
• Marchetti, Barbara
• Karsili, Tolga N. V.
• Lester, Marsha I.

Titel

Photodissociation dynamics of methyl vinyl ketone oxide: A four-carbon unsaturated Criegee intermediate from isoprene ozonolysis

Ist Teil von

• The Journal of chemical physics, 2021-11, Vol.155 (17)

Ort / Verlag

United States: American Institute of Physics (AIP)

Erscheinungsjahr

2021

Quelle

AIP Journals Complete

Beschreibungen/Notizen

• 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. Furthermore, 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.