Cavity-Enhanced Measurements of Hydrogen Peroxide Absorption Cross Sections from 353 to 410 nm

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• 作者：Tara F. Kahan ; Rebecca A. Washenfelder ; Veronica Vaida ; Steven S. Brown
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：June 21, 2012
• 年：2012
• 卷：116
• 期：24
• 页码：5941-5947
• 全文大小：405K
• 年卷期：v.116,no.24(June 21, 2012)
• ISSN：1520-5215

文摘

We report near-ultraviolet and visible absorption cross sections of hydrogen peroxide (H₂O₂) using incoherent broad-band cavity-enhanced absorption spectroscopy (IBBCEAS), a recently developed, high-sensitivity technique. The measurements reported here span the range of 353鈥?10 nm and extend published electronic absorption cross sections by 60 nm to absorption cross sections below 1 脳 10^鈥?3 cm² molecule^鈥?. We have calculated photolysis rate constants for H₂O₂ in the lower troposphere at a range of solar zenith angles by combining the new measurements with previously reported data at wavelengths shorter than 350 nm. We predict that photolysis at wavelengths longer than those included in the current JPL recommendation may account for up to 28% of the total hydroxyl radical (OH) production from H₂O₂ photolysis under some conditions. Loss of H₂O₂ via photolysis may be of the same order of magnitude as reaction with OH and dry deposition in the lower atmosphere; these processes have very different impacts on HO_x loss and regeneration.