Cavity Ringdown Laser Absorption Spectroscopy:  History, Development, and Application to Pulsed Molecular Beams

Scherer, James R.; Paul, J. B.; O’Keefe, Anthony; Saykally, Richard J.

doi:10.1021/cr930048d

Cited by 429 publications

(270 citation statements)

References 83 publications

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“…The CRD technique (Busch and Busch 1999) has traditionally been used for spectroscopic measurements of gas phase molecules (O' Keefe and Deacon 1988;Scherer et al 1997); and more recently for atmospheric measurements of aerosol extinction (Smith and Atkinson 2001;Atkinson 2003;Strawa et al 2003;Pettersson et al 2004;Moosmuller et al 2005). The pulsed CRD technique for aerosol extinction measurements has recently been validated by comparison of measured optical cross-section to calculated optical cross-section for size selected particles of known refractive index (Bulatov et al 2002;Pettersson et al 2004).…”

Section: Measurement Techniquementioning

confidence: 99%

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Baynard

Lovejoy

Pettersson

et al. 2007

Aerosol Science and Technology

104

109

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This paper describes the design and application of a pulsed cavity ring-down aerosol extinction spectrometer (CRD-AES) for insitu atmospheric measurement of the aerosol extinction coefficient and its relative humidity dependence. This CRD-AES measures the aerosol extinction coefficient (σ ep ) at 355 nm, 532 nm, 683 nm, and 1064 nm with a minimal size dependent bias for particles with diameter less than 10 μm. The σ ep at 532 nm is measured with an accuracy of 1% when extinction is ≥10 Mm −1 . The precision is limited by statistical fluctuations within the small optical volume and the time resolution of extinction at 2% uncertainty for various air mass types is evaluated. The CRD-AES is configured with two separate cavity ring-down cells for measurement of the extinction coefficient at 532 nm. This allows the determination of the RH dependence of extinction at 532 nm through independent RH control of the sample for each measurement. Gas phase absorption and minimization of potential interferences is also considered.

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Section: Measurement Techniquementioning

confidence: 99%

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Baynard

Lovejoy

Pettersson

et al. 2007

Aerosol Science and Technology

104

109

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“…16 To the best of our knowledge, the corresponding gas-phase O-D stretches (3.5-4.5 µm) have not been observed previously, primarily because of the lack of suitable radiation sources in this spectral region. The use of cavity ringdown detection 17 greatly relaxes the demands on the light source, and a Raman-shifted pulsed dye laser conveniently provides complete coverage over these wavelengths. In this article we report the measurement and analysis of the hydrogen-bond acceptor antisymmetric O-D stretch in the (D 2 O) 2 isotopomer.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the (D₂O)₂ Hydrogen-Bond-Acceptor Antisymmetric Stretch by IR Cavity Ringdown Laser Absorption Spectroscopy

1998

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The IR-CRLAS technique has been used to measure the mid-infrared O-D stretching spectrum of the fully deuterated gas-phase water dimer for the first time. The instrumentally limited resolution of 1 GHz resolves the acceptor tunneling splittings and the rotational line manifolds. The analysis of these splittings exploits the local nature of the excitation and yields a description of the acceptor tunneling motion that supports previous experimental and theoretical results.

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“…However CRDS is a powerful technique [14][15][16] for dealing with these difficulties. The expected sharp IR transitions should yield resolved vibrational and rotational structure to characterize the peroxy radicals.…”

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Detection and characterization of alkyl peroxy radicals using cavity ringdown spectroscopy

Pushkarsky

Zalyubovsky

Miller

2000

The Journal of Chemical Physics

131

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Cavity ringdown spectra of theÃ 2 A −X 2 A electronic transition in the IR are reported for the methyl and ethyl peroxy radicals. Analysis of partially resolved rotational structure for the origin band of the transition provides information about both theÃ andX states of CH3O2·. An estimate for the absorption cross-section is determined from the CRDS absorption and the rate of radical-radical recombination.Low temperature oxidation of hydrocarbons is a pervasive process in both nature and technology. It is critically important for the environmental quality of our atmosphere. [1][2][3][4][5] Similarly it is critical to the efficiency and fuel economy of internal combustion engines. 6-8 Arguably the most important reaction 7 for low temperature oxidation is the production of peroxy radicals (RO 2 ·) from alkyl radicals (R·), i.e.,There are a number of important alkyl peroxy radicals defined by the nature of the R group, ranging 1 from the simplest species, methyl (R=CH 3 ) peroxy to complex species with R containing at least 8-10 carbon atoms with correspondingly many structural isomers. Because of their significance, much effort 1 has been expended studying the mechanisms and kinetics of peroxy radical production and their subsequent reactions. This work has largely been based upon monitoring of the peroxy radicals via theirB 2 A −X 2 A UV absorption. This is a strong transition, common to all the peroxies, that is centered around 240nm.Unfortunately this transition is broad and unstructured with a half-width of ≈40nm. The quasi-continuum nature of this transition has at least two clear disadvantages. It is unsuitable for obtaining rotational or vibrational information about the radical. Additionally the overlapping of the UV spectra of different RO 2 · radicals makes the identification of a specific alkyl peroxy radical, particularly from a mixture, a significant challenge.Experiments involving the peroxyÃ 2 A −X 2 A transition in the IR are sparse. There was an early report, 9 using low resolution modulated absorption spectroscopy, of the observation of theÃ−X IR transition of several RO 2 · radicals and more recently a report 10 of the observation of fragmentary spectra of ethyl peroxy using a cw absorption technique. There was also a report 11 of the detection of theÃ−X transition of CH 3 O 2 · by intracavity laser absorption spectroscopy, but few spectroscopic details were given. Based upon the recent observation 12 and analysis 13 of a well resolved spectrum of the hydroperoxy radical, HO 2 ·, we expect thẽ A −X IR transitions of the alkyl peroxy radicals to be well structured and observable using cavity ringdown spectroscopy (CRDS).Historically this IR transition has been viewed as difficult to study because of its small oscillator strength (the cross-section σ is ≈ 2 × 10 −21 cm −2 for the corresponding transition 13 in HO 2 ·) and the near IR spectral region (≈ 7000 − 8000 cm −1 ) in which the transition is located. However CRDS is a powerful technique 14-16 for dealing with these difficulties. T...

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Cavity Ringdown Laser Absorption Spectroscopy: History, Development, and Application to Pulsed Molecular Beams

Cited by 429 publications

References 83 publications

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Characterization of the (D₂O)₂ Hydrogen-Bond-Acceptor Antisymmetric Stretch by IR Cavity Ringdown Laser Absorption Spectroscopy

Detection and characterization of alkyl peroxy radicals using cavity ringdown spectroscopy

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Cavity Ringdown Laser Absorption Spectroscopy: History, Development, and Application to Pulsed Molecular Beams

Cited by 429 publications

References 83 publications

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Design and Application of a Pulsed Cavity Ring-Down Aerosol Extinction Spectrometer for Field Measurements

Characterization of the (D2O)2 Hydrogen-Bond-Acceptor Antisymmetric Stretch by IR Cavity Ringdown Laser Absorption Spectroscopy

Detection and characterization of alkyl peroxy radicals using cavity ringdown spectroscopy

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Characterization of the (D₂O)₂ Hydrogen-Bond-Acceptor Antisymmetric Stretch by IR Cavity Ringdown Laser Absorption Spectroscopy