Combined 13C–D and D–D clumping in methane: Methods and preliminary results

Stolper, Daniel A.; Sessions, Alex L.; Ferreira, Anderson A.; Neto, Eugênio V. Santos; Schimmelmann, Arndt; Shusta, S. S.; Valentine, David L.; Eiler, John M.

doi:10.1016/j.gca.2013.10.045

Cited by 148 publications

(277 citation statements)

References 49 publications

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“…yields practically identical value to that defined by Stolper et al (2014) 3 that referenced against "stochastic 13 CH 3 D abundance", which is estimated from 13 CH 4 and 12 CH 3 D. This is because,…”

supporting

confidence: 61%

“…The definition of Δ 13 CH 3 D in equation (3) yields values that are practically identical to those 114 calculated using the definition used by Stolper et al (2014) 21 (i.e., the deviation from stochastic 115 distribution. see SI).…”

mentioning

confidence: 79%

“…29 was achieved for the measurement of 13 CH 3 temperatures. The TILDAS instrument offers a simple and precise method to determine 13 CH 3 D 35 in natural methane samples to distinguish geological and biological sources of methane in the 36 atmosphere, hydrosphere, and lithosphere.…”

mentioning

confidence: 99%

“…For practical purposes (under expected ranges of multiply-substituted isotopologue abundance 119 for natural samples), δ 13 CH 4 is identical to δ 13 C and δ 12 CH 3 were synthesized for spectral characterization and to produce a series of working standard gases. 124…”

mentioning

confidence: 99%

“…A sample gas inlet system was developed for 344 the TILDAS, with which a precision of 0.2‰ (2σ) and an accuracy of 0.7 ‰ (2σ) were achieved 345 for the measurement of Δ 13 CH 3 Table 2. Isotopologue compositions for laboratory cylinder methane (AL1, AS1 and AS2).…”

mentioning

confidence: 99%

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Measurement of a Doubly Substituted Methane Isotopologue, ¹³CH₃D, by Tunable Infrared Laser Direct Absorption Spectroscopy

et al. 2014

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Methane is an important energy resource and significant long-lived greenhouse gas. Carbon and hydrogen isotope ratios have been used to better constrain the sources of methane but interpretations based on these two parameters alone can often be inconclusive. The precise measurement of a doubly substituted methane isotopologue, 13CH3D, is expected to add a critical new dimension to source signatures by providing the apparent temperature at which methane was formed or thermally equilibrated. We have developed a new method to precisely determine the relative abundance of 13CH3D by using tunable infrared laser direct absorption spectroscopy (TILDAS). The TILDAS instrument houses two continuous wave quantum cascade lasers; one tuned at 8.6 μm to measure 13CH3D, 12CH3D, and 12CH4, and the other at 7.5 μm to measure 13CH4. With the use of an astigmatic Herriott cell with an effective path length of 76 m, a precision of 0.2‰ (2σ) was achieved for the measurement of 13CH3D abundance in ca. 10 mL STP (i.e., 0.42 mmol) pure methane samples. Smaller quantity samples (ca. 0.5 mL STP) can be measured at lower precision. The accuracy of the Δ13CH3D measurement is 0.7‰ (2σ), evaluated by thermally equilibrating methane with a range of δD values. The precision of ±0.2‰ corresponds to uncertainties of ±7 °C at 25 °C and ±20 °C at 200 °C for estimates of apparent equilibrium temperatures. The TILDAS instrument offers a simple and precise method to determine 13CH3D in natural methane samples to distinguish geological and biological sources of methane in the atmosphere, hydrosphere, and lithosphere.

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supporting

confidence: 61%

mentioning

confidence: 79%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Measurement of a Doubly Substituted Methane Isotopologue, ¹³CH₃D, by Tunable Infrared Laser Direct Absorption Spectroscopy

et al. 2014

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Rapid photochemical equilibration of isotope bond ordering in O₂

2014

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Clumped isotope perturbation in tropospheric nitrous oxide from stratospheric photolysis

Schmidt

Johnson

2015

Geophysical Research Letters

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Nitrous oxide (N2O) is potent greenhouse gas and source of ozone depleting NO to the stratosphere. Recent advances in mass spectrometry allow accurate measurement of multiply substituted (“clumped”) N2O isotopocules, providing new constraints on the N2O source budget. However, this requires a quantification of the “clumped” N2O fractionation from stratospheric photolysis (main sink). We use time‐dependent quantum dynamics and a 1‐D atmospheric model to determine the effect of stratospheric photolysis on the abundances of multisubstituted N2O isotopocules in the atmosphere. The ultraviolet absorption cross sections of 557 (i.e., 15N15N17O), 458, 548, 457, and 547 are presented for the first time and used to derive altitude‐dependent photolysis rates and fractionation constants. We find that photolysis alters the N2O isotopic composition with multisubstituted mass 47 isotopocules being less abundant than expected from stochastics (Δ47 = −1.7‰ in the troposphere and down to −12‰ in the upper stratosphere).

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Combined 13C–D and D–D clumping in methane: Methods and preliminary results

Cited by 148 publications

References 49 publications

Measurement of a Doubly Substituted Methane Isotopologue, ¹³CH₃D, by Tunable Infrared Laser Direct Absorption Spectroscopy

Measurement of a Doubly Substituted Methane Isotopologue, ¹³CH₃D, by Tunable Infrared Laser Direct Absorption Spectroscopy

Rapid photochemical equilibration of isotope bond ordering in O₂

Clumped isotope perturbation in tropospheric nitrous oxide from stratospheric photolysis

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Combined 13C–D and D–D clumping in methane: Methods and preliminary results

Cited by 148 publications

References 49 publications

Measurement of a Doubly Substituted Methane Isotopologue, 13CH3D, by Tunable Infrared Laser Direct Absorption Spectroscopy

Measurement of a Doubly Substituted Methane Isotopologue, 13CH3D, by Tunable Infrared Laser Direct Absorption Spectroscopy

Rapid photochemical equilibration of isotope bond ordering in O2

Clumped isotope perturbation in tropospheric nitrous oxide from stratospheric photolysis

Contact Info

Product

Resources

About

Measurement of a Doubly Substituted Methane Isotopologue, ¹³CH₃D, by Tunable Infrared Laser Direct Absorption Spectroscopy

Measurement of a Doubly Substituted Methane Isotopologue, ¹³CH₃D, by Tunable Infrared Laser Direct Absorption Spectroscopy

Rapid photochemical equilibration of isotope bond ordering in O₂