Cavity ringdown spectroscopy measurements of the infrared water vapor continuum

Cormier, John G.; Ciuryło, R.; Drummond, J. R.

doi:10.1063/1.1425825

Cited by 35 publications

(19 citation statements)

References 30 publications

(29 reference statements)

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“…This is because laser spray relies on the absorption of 10.6 m infrared laser, mainly by water solvent. With water solvent temperature rising [40], the absorption coefficient decreases drastically, and thus the heating of biological samples is self-limiting. This makes it possible to extract labile biological molecules in solution to the gas phase under very mild conditions.…”

Section: Resultsmentioning

confidence: 99%

Denaturation of lysozyme and myoglobin in laser spray

Takamizawa

Fujimaki

Sunner

et al. 2005

J. Am. Soc. Mass Spectrom.

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In laser spray, the tip of an electrospray capillary is irradiated with a continuous CO(2) laser beam. Here, we report results from a modified laser spray method that employs a relatively low laser irradiance level. With a laser power of approximately 2 W and a focal spot size ( approximately 0.3 mm), which covered the entire front surface of the electrospray capillary, the irradiance was approximately 3 x 10(3) W/cm(2). This resulted in a quiescent and smooth vaporization of aqueous solutions. This "evaporation-mode" laser spray method yielded the best results so far obtained in our laboratory with laser-irradiated electrospray, producing higher and more stable signals. The method was applied to the analysis of aqueous solutions of lysozyme and myoglobin. Mass spectra were obtained as a function of laser power from 0 W (electrospray) to approximately 2 W. The spray generated at the tip of the stainless steel capillary was observed with a CCD camera. With increase of laser power, the droplets in the spray became finer and the Taylor cone became progressively smaller. The strongest ion signals were recorded when the sample solution protruded only slightly from the tip of the capillary. A broadening of the lysozyme charge-state distribution, attributable to protein unfolding, was observed with a laser power of 2 W. No denaturation of myoglobin took place up to a laser power of 1.6 W. However, a sudden onset of denaturation was observed at 1.8 W as a broadening of the myoglobin charge distribution and the appearance of apo-myoglobin peaks. These findings demonstrate that laser spray is capable of dissociating the noncovalent complexes selectively without breaking covalent bonds.

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Section: Resultsmentioning

confidence: 99%

Denaturation of lysozyme and myoglobin in laser spray

Takamizawa

Fujimaki

Sunner

et al. 2005

J. Am. Soc. Mass Spectrom.

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“…It has been suggested that the continuum may be caused by the far wings of allowed transitions of the water vapor monomer. The theory used to estimate the line shapes further from line centers is often referred to as ‘far wing theory’ and has been shown to describe the observed far wing self‐and foreign‐continuum accurately from 300–1000 cm −1 [ Cormier et al , 2002; Davies et al , 1982; Ma and Tipping , 2000; Ma and Tipping , 2002; Rosenkranz , 1985]. Another proposed cause of the water vapor continuum is the presence of bound water complexes.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric water vapor complexes and the continuum

Daniel

Solomon

Kjaergaard

et al. 2004

Geophysical Research Letters

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[1] Estimates of absorption optical depths for the bound complexes H 2 O-H 2 O and the sum of H 2 O-N 2 , H 2 O-O 2 , and H 2 O-Ar at visible and near-infrared wavelengths are compared to the same quantities calculated from a frequently used water continuum parameterization (MT_CKD) and from a theoretical far wing water vapor lineshape theory. The temperature dependences of some of these optical depths are also compared. The comparisons suggest qualitatively that water complexes may contribute to the continuum at these wavelengths, and show that the temperature dependence of the continuum might provide insight into the role of the complexes in the atmosphere. Because of the dearth of laboratory measurements of the continuum at these wavelengths, and because the current estimates for the equilibrium constants of these water vapor complexes remain highly uncertain, more observations are needed before the importance of water complexes can be accurately quantified.

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“…for different gases) and spectral regions. This theory seemed to be reasonably good in describing the experimentally derived water vapour continuum in the mid-infrared spectral region including the wing of the rotational band (see e.g., Cormier et al 2002); however, the model significantly underestimates continuum absorption within bands. The authors of the model explain this by the fact that their far-wing formalism is inapplicable closer to band centres.…”

Section: -2000mentioning

confidence: 96%

“…Cormier et al (2002) Fig. 3 Self-and foreign-continuum cross-section (upper and lower panels respectively) as retrieved from laboratory measurements in Ptashnik et al (2011bPtashnik et al ( , 2012 (CAVIAR), along with their associated uncertainties, compared to the far-wing model of Tipping and Ma (1995) and the MTCKD-2.5 continuum model Surv Geophys (2012) 33:535-555 547 presented evidence that the spectral variation in the mid-infrared window was consistent with the Ma and Tipping (1999) far-wing line theory, whilst Cormier et al (2005) presented one of the most detailed analyses of the temperature dependence in this window at near-atmospheric conditions, which they found to be in good agreement with Vigasin's (2000) parameterisation for water complexes.…”

Section: Post-2000mentioning

confidence: 97%