The CH₃CO quantum yield in the 248 nm photolysis of acetone, methyl ethyl ketone, and biacetyl

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• 作者：B. Rajakumar ; Tomasz Gierczak ; Jonathan E. Flad ; A.R. Ravishankara ; James B. Burkholder
• 关键词：Acetyl radical ; Acetone ; Photolysis ; Quantum yield
• 刊名：Journal of Photochemistry and Photobiology A: Chemistry
• 出版年：2008
• 出版时间：25 September 2008
• 年：2008
• 卷：199
• 期：2-3
• 页码：336-344
• 全文大小：593 K

文摘

We report measurements of the CH₃CO quantum yield, Φ_CH3CO, following the 248 nm pulsed laser photolysis of acetone (CH₃C(O)CH₃), methyl ethyl ketone (CH₃C(O)CH₂CH₃), and biacetyl (CH₃C(O)C(O)CH₃). CH₃CO quantum yields at 248 nm were measured at 296 K, relative to CH₃CO reference systems. CH₃CO was detected using cavity ring-down spectroscopy at wavelengths between 490 and 660 nm. Measurements were performed between 60 and 670 Torr (He, N₂ bath gases) and the obtained CH₃CO quantum yields in the low-pressure limit, , were 0.535 ± 0.09, 0.41 ± 0.08, and 0.76 ± 0.11, for acetone, methyl ethyl ketone, and biacetyl, respectively. The quoted uncertainties are 2c3; (95 % confidence level) and include estimated systematic errors. An increase in Φ_CH3CO with increasing bath gas pressure, which depended on the identity of the collision partner (He, N₂), was observed. The present results are compared with previous quantum yield determinations.