Photodissociation Dynamics of the i-Methylvinoxy Radical at 308, 248, and 225 nm Using Fast Beam Photofragment Translational Spectroscopy

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• 作者：Bethan NicholsErin. N. Sullivan ; Mikhail Ryazanov ; Daniel M. Neumark
• 刊名：Journal of Physical Chemistry A
• 出版年：2017
• 出版时间：January 26, 2017
• 年：2017
• 卷：121
• 期：3
• 页码：579-586
• 全文大小：405K
• ISSN：1520-5215

文摘

The photodissociation dynamics of the i-methylvinoxy (CH₃COCH₂) radical have been studied by means of fast beam coincidence translational spectroscopy. The radical was produced by photodetachment of the i-methylvinoxide anion at 700 nm, followed by dissociation at 225 nm (5.51 eV), 248 nm (5.00 eV), and 308 nm (4.03 eV). At all three dissociation energies, the major products were found to be CH₃ + CH₂CO, with a small amount of CO + C₂H₅ produced at the higher dissociation energies. Photofragment mass distributions and translational energy distributions were recorded for each wavelength. Comparison of the mass distributions with dissociation of fully deuterated i-methylvinoxy aided the assignment of the observed channels. Electronic structure calculations were performed to determine the relative energies of minima and transition states involved in the dissociation and to aid interpretation of the experimental results. The proposed dissociation mechanism involves internal conversion from the initially excited electronic state, followed by dissociation over a barrier on the ground state.