skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

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

Abstract

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

Citation Formats

Thurlow, M. E., E-mail: thurlow@huarp.harvard.edu, Hannun, R. A., Lapson, L. B., Anderson, J. G., Co, D. T., Argonne-Northwestern Solar Energy Research Center and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, O'Brien, A. S., Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544, Hanisco, T. F., and NASA Goddard Space Flight Center, Code 614, Greenbelt, Maryland 20771. The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals. United States: N. p., 2014. Web. doi:10.1063/1.4869857.
Thurlow, M. E., E-mail: thurlow@huarp.harvard.edu, Hannun, R. A., Lapson, L. B., Anderson, J. G., Co, D. T., Argonne-Northwestern Solar Energy Research Center and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, O'Brien, A. S., Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544, Hanisco, T. F., & NASA Goddard Space Flight Center, Code 614, Greenbelt, Maryland 20771. The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals. United States. doi:10.1063/1.4869857.
Thurlow, M. E., E-mail: thurlow@huarp.harvard.edu, Hannun, R. A., Lapson, L. B., Anderson, J. G., Co, D. T., Argonne-Northwestern Solar Energy Research Center and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, O'Brien, A. S., Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544, Hanisco, T. F., and NASA Goddard Space Flight Center, Code 614, Greenbelt, Maryland 20771. Tue . "The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals". United States. doi:10.1063/1.4869857.
@article{osti_22254930,
title = {The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals},
author = {Thurlow, M. E., E-mail: thurlow@huarp.harvard.edu and Hannun, R. A. and Lapson, L. B. and Anderson, J. G. and Co, D. T. and Argonne-Northwestern Solar Energy Research Center and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 and O'Brien, A. S. and Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544 and Hanisco, T. F. and NASA Goddard Space Flight Center, Code 614, Greenbelt, Maryland 20771},
abstractNote = {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 point measurements of IO in North America.},
doi = {10.1063/1.4869857},
journal = {Review of Scientific Instruments},
number = 4,
volume = 85,
place = {United States},
year = {Tue Apr 15 00:00:00 EDT 2014},
month = {Tue Apr 15 00:00:00 EDT 2014}
}
  • An instrument for the measurement of tropospheric OH radical concentrations by laser-induced fluorescence spectroscopy has been developed. Ambient air is expanded through a nozzle into a low-pressure fluorescence cell and is irradiated by a frequency-doubled dye laser, which is pulsed with a high repetition rate of 8.5 kHz. The laser wavelength is tunable to selectively excite single rovibronic transitions of the OH radicals at 308 nm [A{sup 2}{Sigma}{sup +} (v{prime} = 0) {yields} X {sup 2}{Pi} (v{double_prime} = 0)]. The OH resonance fluorescence, emitted mostly between 307 and 311 nm, is detected by gated photon counting. From laboratory calibrations andmore » ambient air measurements the authors infer a detection limit (S/N = 2) of 8 X 10{sup 5} OH cm{sup {minus}3} for 1-minute data integration time. First tests of the new instrument in ambient air revealed the existence of an interference problem due to generation of OH by a dark reaction of ozone inside the detection cell. Improvements of the instrument reduced the spurious OH signal to a level corresponding to an ambient OH concentration of 3 X 10{sup {minus}3}, thus being within the detection limit of the instrument. During a sunny and clear period in May-June 1994 the instrument was tested in the field. For the first time it was possible to record excitation spectra of tropospheric OH comprising the Q{sub 1}(3), Q{sub 21}(3), and P{sub 1}(1) rotational lines. THe analysis of the data yielded hydroxyl radical concentrations of up to 4 X 10{sup 6} molecules cm{sup {minus}3}. These spectra unambiguously identify the OH radical and demonstrate the high detection sensitivity and selectivity of this new instrument. 20 refs., 4 figs., 1 tab.« less
  • The odd-hydrogen radicals OH and HO2 are central to most of the gas-phase chemical transformations that occur in the atmosphere. Of particular interest is the role that these species play in controlling the concentration of stratospheric ozone. This paper describes an instrument that measures both of these species at volume mixing ratios below one part in 10(exp 14) in the upper troposphere and lower stratosphere. The hydroxyl radical (OH) is measured by laser induced fluorescence at 309 nm. Tunable UV light is used to pump OH to the first electric state near 282 nm. the laser light is produced bymore » a high-repetition rate pulsed dye-laser powered with all solid-state pump lasers. HO2 is measured as OH after gas-phase titration with nitric oxide. Measurements aboard a NASA ER-2 aircraft demonstrate the capability of this instrument to perform reliably with very high signal-to-noise ratios (greater than 30) achieved in short integration times (less than 20 sec).« less
  • Laser-induced fluorescence spectroscopy was used to detect ground-state CF/sub 2/ radicals in 13.56-MHz discharge plasmas sustained in C/sub 2/F/sub 6/ and CF/sub 4/ in a plasma etching reactor. Measurements of the relative CF/sub 2/(X) density in each plasma as a function of discharge power demonstrated that CF/sub 2/ densities were significantly higher in the C/sub 2/F/sub 6/ plasma. These results provide the first direct observation of CF/sub 2/(X) radicals in a plasma etching reactor.
  • The effect of atmospheric air pressure on the intensity of iodine-129 vapor fluorescence excited by a He-Ne (633 nm) laser is studied. It is shown that to achieve the maximum intensity of fluorescence of molecular iodine-129, it is advantageous, first, to use a {sup 3}He-{sup 20}Ne laser for excitation, and second, to detect atmospheric iodine impurities in the gas mixture under analysis evacuated to 2 x 10{sup 18} - 4 x 10{sup 18} mol/cm{sup 3}. In this case, the sensitivity increases about twofold. 7 refs., 4 figs.
  • Isotopically specific fluorescence detection of elemental iodine-129 has been investigated with a broad-band dye laser system. The intracavity spoiling phenomenon was utilized in this investigation to achieve isotopic specificity and to effect a modulated fluorescence signal. This rugged laser-based analytical system was found to exhibit a conventional linear relationship between signal level and analyte concentration, although laser-based instabilities limited detection limits of this approach to concentrations greater than 10/sup 10/ molecules/cm/sup 3/. Fluorescence measurements were also accomplished by direct single frequency excitation of /sup 129/I/sub 2/. This method of excitation exhibited a fluorescence detection limit of 2 x 10/sup 9/more » molecules/cm/sup 3/ and proved to be more sensitive than the broad-band approach.« less