Prototype for In Situ Detection of Atmospheric NO3 and N2O5 via Laser-Induced Fluorescence

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• 作者：Ezra C. Wood ; Paul J. Wooldridge ; Jens H. Freese ; Tim Albrecht ; and Ronald C. Cohen
• 刊名：Environmental Science & Technology
• 出版年：2003
• 出版时间：December 15, 2003
• 年：2003
• 卷：37
• 期：24
• 页码：5732 - 5738
• 全文大小：117K
• 年卷期：v.37,no.24(December 15, 2003)
• ISSN：1520-5851

文摘

We describe a prototype designed for in situ detection ofthe nitrate radical (NO₃) by laser-induced fluorescence(LIF) and of N₂O₅ by thermal dissociation followed by LIFdetection of NO₃. An inexpensive 36 mW continuous wavemulti-mode diode laser at 662 nm is used to excite NO₃in the ²E'(0000) journals/esthag/37/i24/eqn/es034507we10001.gif"> band. Fluorescence iscollected from 700 to 750 nm. The prototype has a sensitivityto NO₃ of 76 ppt for a 60 s integration with an accuracyof 8%. Although this sensitivity is adequate for studies ofN₂O₅ in many environments, it is much less sensitive (about300 times) than expected based on a comparison ofpreviously measured photophysical properties of NO₂ andNO₃. This implies much stronger nonradiative couplingof electronic states in NO₃ than in NO₂.