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Title: The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals

High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10{sup 12}. The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A{sup 2}Π{sub 3/2} (v{sup ′} = 2) ← X{sup 2}Π{sub 3/2} (v{sup ″} = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ pointmore » measurements of IO in North America.« less
Authors:
; ; ;  [1] ;  [1] ;  [2] ;  [1] ;  [2] ;  [1] ;  [2]
  1. Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22254930
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BOUNDARY LAYERS; FLUORESCENCE; IODINE; MERCURY; MIXING RATIO; NEODYMIUM LASERS; PHOTOCHEMISTRY; RADICALS; SAPPHIRE; SENSITIVITY; SIGNAL-TO-NOISE RATIO; VALIDATION; VISIBLE RADIATION; WAVELENGTHS