Atmospheric trace gas analysis with cavity ring‐down spectroscopy

Kleine, D.; Mürtz, Manfred; Lauterbach, Jörg; Dahnke, Hannes; Urban, W.; Hering, P.; Kleinermanns, Karl

doi:10.1560/r4db-ad8n-687h-105g

Cited by 8 publications

(11 citation statements)

References 30 publications

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“…The cavity ring-down (CRD) technique, using pulsed tunable lasers, has undergone a recent application explosion. Since its introduction in 1988, the appeal of CRD in providing a sensitive variant of absorption spectroscopy has resulted in its application to chemical problems ranging from surface phenomena , to process measurements in plasmas and flames, − to atmospheric studies, − and to a wide range of chemical kinetics studies. ,,− Some of the recent applications of CRD spectroscopy and variants of the basic technique are summarized in the chemical literature. − …”

Section: Methodsmentioning

confidence: 99%

Alkyl Peroxy Radical Kinetics Measured Using Near-infrared CW−Cavity Ring-down Spectroscopy

Atkinson

Spillman

2002

J. Phys. Chem. A

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A kinetic reactor system is described which couples pulsed laser photolytic production of radicals with continuous laser excitation cavity ring-down spectroscopic detection in the near-infrared (NIR). The atmospherically relevant alkyl peroxy radicals ethyl peroxy (C2H5O2) and methyl peroxy (CH3O2) were monitored via their structured absorbance spectra in the NIR near 1.3 μm. These peroxy radicals were then subjected to kinetic study as proof-of-principle for the new technique. Portions of the absorption spectra for the two radicals are reported which agree well with previously published spectra [Hunziker, H. E.; Wendt, H. R. J. Chem. Phys. 1976, 64, 3488. Pushkarsky, M. B.; Zalyubovsky, S. J.; Miller, T. A. J. Chem. Phys. 2000, 112, 10695]. The absorption cross sections were determined at selected wavelengths using the known self-reaction rate coefficients and observed kinetic data. The absorption cross sections determined are as follows: for two of the maxima in the origin band of C2H5O2, σ1317.01 nm = σ1316.40 nm = (3.0 ± 1.5) × 10-21 cm2 molecule-1, and for a maximum in a sequence band of CH3O2, σ1335.07 nm = (1.5 ± 0.8) × 10-20 cm2 molecule-1. Preliminary data for the prototypical peroxy radical cross-reaction between CH3O2 and C2H5O2 is presented. This data supports earlier work [Villenave, E.; Lesclaux, R. J. Phys. Chem. 1996, 100, 14372] which established a pressure independent value of k(CH3O2 + CH3CH2O2) = 2.0 × 10-13 cm3 molecule-1 s-1 at 298 K. As in most kinetic studies involving peroxy radicals, the accuracy of the reported rate coefficients is influenced by the details of the complex mechanisms used in the fitting. However, in the current studies, specific radical absorption(s) are used to follow each radical's decay, which should improve the precision of the determination.

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Section: Methodsmentioning

confidence: 99%

Alkyl Peroxy Radical Kinetics Measured Using Near-infrared CW−Cavity Ring-down Spectroscopy

Atkinson

Spillman

2002

J. Phys. Chem. A

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“…As we await further developments in UV and mid-IR laser sources based on diode laser technology, frequency and wavelength modulation (FM and WM) methods, coupled with multipass cells and benefiting from stronger molecular absorptions in the mid-IR and UV wavelength regions, are sufficient for many of the types of applications reviewed earlier. Most cw CRDS and CEAS laboratory work in the mid IR has used laser sources such as CO gas lasers and OPOs, [184][185][186]189 but quantum cascade lasers, operating in the mid and far-IR, also have the potential to revolutionise trace gas measurements. There are a few examples of use of QC lasers in cw CRDS 190,191 and CEAS 113 measurements, with greatest sensitivities so far demonstrated in the more technically complex CRDS experiments.…”

Section: Anticipated Future Developmentsmentioning

confidence: 99%

4 Cavity ring-down and cavity enhanced spectroscopy using diode lasers

Mazurenka

Orr-Ewing

Peverall

et al. 2005

Annu. Rep. Prog. Chem., Sect. C

236

174

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Continuous wave (cw) diode lasers are increasingly being used as light sources in the visible and near-IR regions of the spectrum for cavity ringdown spectroscopy (CRDS) and cavity enhanced absorption spectroscopy (CEAS); the latter technique is also widely known as integrated cavity output spectroscopy (ICOS). The very high sensitivities to weak absorptions that are possible with cw CRDS and CEAS, coupled with the quantitative nature of the absorption measurements, are enabling a rapidly expanding range of applications. We review the benefits and practical implementation of these techniques; methods of data analysis for extraction of quantitative absorption data; the sensitivities of cw CRDS and CEAS, and how they might be optimised; and applications of cw CRDS and CEAS in molecular spectroscopy, atmospheric chemistry, plasma and flame chemistry, analytical science, and medical diagnosis via breath analysis. The development of CRDS and CEAS techniques exploiting cw diode lasers and, very recently, high luminosity light-emitting diodes, has stimulated a wealth of highsensitivity measurements. Highlights include quantitative measurement of various ultra-trace gases such as: NO 3 , NO 2 and ethene in ambient air samples; CO 2 isotopologues, ethane and other organic compounds in human breath samples; and excited electronic states of N 2 and O 2 in plasmas and discharges. Exciting developments include wavelength extension into the mid-IR and UV regions, and use of novel locked-cavity techniques to increase data acquisition rates and sensitivities.

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“…The ultraviolet is a region where many compounds possess strong electronic absorption spectra; it is, however, a difficult region for sensitive HFCAS detection. 44 Although pulsed laser sources that cover the entire UV are readily available (e.g., frequencydoubled dye lasers, fixed frequency Nd:YAG harmonics, and excimer lasers), high-reflectivity UV mirror coatings are not as efficient. Rayleigh and Mie scattering processes have steep wavelength dependences and contribute significantly to the loss from an optical cavity at or near ambient pressure.…”

Section: Spectral Regionsmentioning

confidence: 99%