Incoherent Broadband Cavity-Enhanced Absorption Spectroscopy in the near-Ultraviolet: Application to HONO and NO<sub>2</sub>

Gherman, Titus; Venables, Dean S.; Vaughan, Stewart; Orphal, J.; Ruth, Albert A.

doi:10.1021/es0716913

Cited by 153 publications

(134 citation statements)

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“…The technique has proved valuable for quantifying trace gases and aerosol extinction in chamber and field measurements (Venables et al, 2006;Dixneuf et al, 2009;Ball et al, 2010;Thalman and Volkamer, 2010;Washenfelder et al, 2008) and good agreement with other techniques has been demonstrated in recent intercomparisons of NO 2 and NO 3 measurements (Dorn et al, 2011;Fuchs et al, 2010). Most IBBCEAS measurements thus far have been at visible wavelengths, with the shortest wavelength measurements between 360 nm and 380 nm to quantify HONO and NO 2 (Gherman et al, 2008). To our knowledge, however, the technique has not been employed to record high quality reference spectra.…”

Section: Introductionmentioning

confidence: 85%

A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases

Chen

Venables

2011

Atmos. Meas. Tech.

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Abstract. Accurate absorption spectra of gases in the nearultraviolet (300 to 400 nm) are essential in atmospheric observations and laboratory studies. This paper describes a novel incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) instrument for measuring very weak absorption spectra from 335 to 375 nm. The instrument performance was validated against the 3 B 1 -X 1 A 1 transition of SO 2 . The measured absorption varied linearly with SO 2 column density and the resulting spectrum agrees well with published spectra. Using the instrument, we report new absorption cross-sections of O 3 , acetone, 2-butanone, and 2-pentanone in this spectral region, where literature data diverge considerably. In the absorption minimum between the Huggins and Chappuis bands, our absorption spectra fall at the lower range of reported ozone absorption crosssections. The spectra of the ketones agree with prior spectra at moderate absorptions, but differ significantly at the limits of other instruments' sensitivity. The collision-induced absorption of the O 4 dimer at 360.5 nm was also measured and found to have a maximum cross-section of ca. 4.0 × 10 −46 cm 5 molecule −2 . We demonstrate the application of the instrument to quantifying low concentrations of the shortlived radical, BrO, in the presence of stronger absorptions from Br 2 and O 3 .

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Section: Introductionmentioning

confidence: 85%

A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases

Chen

Venables

2011

Atmos. Meas. Tech.

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“…HONO and NO 2 outputs from the calibration source were measured using an incoherent broadband cavity enhanced absorption spectrometer (IB-BCEAS) (Washenfelder et al, 2009). IBBCEAS employs broadband light that is coupled into a high-finesse optical cavity to achieve a long effective pathlength, and has been used previously for measurements of HONO (Gherman et al, 2008;Langridge et al, 2009). The IBBCEAS instrument was modified for spectral measurements in the 357-372 nm region using a Nichia NCSU033A(T) UV LED and cavity mirrors (Advanced Thin Films) with manufacturer reported transmission of 0.0082% at their nominal center wavelength 362 nm.…”

Section: Ni-pt-cimsmentioning

confidence: 99%

Measurement of HONO, HNCO, and other inorganic acids by negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS): application to biomass burning emissions

et al. 2010

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Abstract. A negative-ion proton-transfer chemical ionization mass spectrometric technique (NI-PT-CIMS), using acetate as the reagent ion, was applied to the measurement of volatile inorganic acids of atmospheric interest: hydrochloric (HCl), nitrous (HONO), nitric (HNO 3 ), and isocyanic (HNCO) acids. Gas phase calibrations through the sampling inlet showed the method to be intrinsically sensitive (6-16 cts/pptv), but prone to inlet effects for HNO 3 and HCl. The ion chemistry was found to be insensitive to water vapor concentrations, in agreement with previous studies of carboxylic acids. The inlet equilibration times for HNCO and HONO were 2 to 4 s, allowing for measurement in biomass burning studies. Several potential interferences in HONO measurements were examined: decomposition of HNO 3 ·NO − 3 clusters within the CIMS, and NO 2 -water production on inlet surfaces, and were quite minor (≤1%, 3.3%, respectively). The detection limits of the method were limited by the instrument backgrounds in the ion source and flow tube, and were estimated to range between 16 and 50 pptv (parts per trillion by volume) for a 1 min average. The comparison of HONO measured by CIMS and by in situ FTIR showed good correlation and agreement to within 17%. The method provided rapid and accurate measurements of HNCO and HONO in controlled biomass burning studies, in which both acids were seen to be important products.

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“…When the optical cross section of the analyte species is known, the gas-phase concentration of the species may be calculated directly from the optical extinction. IBBCEAS has been used successfully to measure gas phase concentrations of NO 2 , NO 3 , CHOCHO, CH 3 COCHO, HONO, O 3 , I 2 , IO, and OIO (Ball et al, 2004;Venables et al, 2006;Washenfelder et al, 2008;Gherman et al, 2008;Vaughan et al, 2008;Thalman and Volkamer, 2010). Initial cavity measurements have reported aerosol extinction for ambient aerosol (Washenfelder et al, 2008;Varma et al, 2009;Thalman and Volkamer, 2010).…”

Section: Introductionmentioning

confidence: 99%

Broadband measurements of aerosol extinction in the ultraviolet spectral region

et al. 2013

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Aerosols influence the Earth's radiative budget by scattering and absorbing incoming solar radiation. The optical properties of aerosols vary as a function of wavelength, but few measurements have reported the wavelength dependence of aerosol extinction cross sections and complex refractive indices. We describe a new laboratory instrument to measure aerosol optical extinction as a function of wavelength, using cavity enhanced spectroscopy with a broadband light source. The instrument consists of two broadband channels which span the 360–390 and 385–420 nm spectral regions using two light emitting diodes (LED) and a grating spectrometer with charge-coupled device (CCD) detector. We determined aerosol extinction cross sections and directly observed Mie scattering resonances for aerosols that are purely scattering (polystyrene latex spheres and ammonium sulfate), slightly absorbing (Suwannee River fulvic acid), and strongly absorbing (nigrosin dye). We describe an approach for retrieving refractive indices as a function of wavelength from the measured extinction cross sections over the 360–420 nm wavelength region. The retrieved refractive indices for PSL and ammonium sulfate agree within uncertainty with the literature values for this spectral region. The refractive index determined for nigrosin is 1.78 (± 0.03) + 0.19 (± 0.08)i at 360 nm and 1.63 (± 0.03) + 0.21 (± 0.05)i at 420 nm. The refractive index determined for Suwannee River fulvic acid is 1.71 (± 0.02) + 0.07 (± 0.06)i at 360 nm and 1.66 (± 0.02) + 0.06 (± 0.04)i at 420 nm. These laboratory results support the potential for a field instrument capable of determining ambient aerosol optical extinction, average aerosol extinction cross section, and complex refractive index as a function of wavelength

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Incoherent Broadband Cavity-Enhanced Absorption Spectroscopy in the near-Ultraviolet: Application to HONO and NO₂

Cited by 153 publications

References 59 publications

A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases

A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases

Measurement of HONO, HNCO, and other inorganic acids by negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS): application to biomass burning emissions

Broadband measurements of aerosol extinction in the ultraviolet spectral region

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Incoherent Broadband Cavity-Enhanced Absorption Spectroscopy in the near-Ultraviolet: Application to HONO and NO2

Cited by 153 publications

References 59 publications

A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases

A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases

Measurement of HONO, HNCO, and other inorganic acids by negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS): application to biomass burning emissions

Broadband measurements of aerosol extinction in the ultraviolet spectral region

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Incoherent Broadband Cavity-Enhanced Absorption Spectroscopy in the near-Ultraviolet: Application to HONO and NO₂