Global Fitting of 12c16o2 Vibrational–rotational Line Positions Using the Effective Hamiltonian Approach

Tashkun, S.A.; Perevalov, V.I.; Teffo, J.-L.; Rothman, Laurence S.; Tyuterev, Vladimir G.

doi:10.1016/s0022-4073(98)00082-x

Cited by 113 publications

(96 citation statements)

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“…We compared the CO 2 (g) vibrational frequencies and C@O bond lengths using each method/basis set combination with measured frequencies, corrected for anharmonicity (Table A4) (Tashkun et al, 1998;Ding et al, 2004). The QCISD/6-311++G(2d,2p) model has the smallest rootmean squared misfit (RMS 11 ) (13.8 cm…”

Section: A22 Comparison Of Measured and Model Co 2 (G) Vibrationalmentioning

confidence: 99%

Theoretical constraints on the effects of pH, salinity, and temperature on clumped isotope signatures of dissolved inorganic carbon species and precipitating carbonate minerals

Hill

Tripati

Schauble

2014

Geochimica et Cosmochimica Acta

146

194

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The use of carbonate 'clumped isotope' thermometry as a geochemical technique to determine temperature of formation of a carbonate mineral is predicated on the assumption that the mineral has attained an internal thermodynamic equilibrium. If true, then the clumped isotope signature is dependent solely upon the temperature of formation of the mineral without the need to know the isotopic or elemental composition of coeval fluids. However, anomalous signatures can arise under disequilibrium conditions that can make the estimation of temperatures uncertain by several degrees Celsius. Here we use ab initio calculations to examine the potential disequilibrium mineral signatures that may arise from the incorporation of dissolved inorganic carbon (DIC) species (predominantly aqueous carbonate and bicarbonate ions) into growing crystals without full equilibration with the crystal lattice.We explore theoretically the nature of clumping in the individual DIC species and the composite DIC pool under varying pH, salinity, temperature, and isotopic composition, and speculate about their effects upon the resultant disequilibrium clumping of the precipitates. We also calculate equilibrium clumped signatures for the carbonate minerals calcite, aragonite, and witherite. Our models indicate that each DIC species has a distinct equilibrium clumped isotope signature such that, (witherite). We define the calcite clumped crossover pH as the pH at which the composite D 47 (DIC pool) = D 47 (equilibrium calcite). If disequilibrium D 47 (calcite) is misinterpreted as equilibrium D 47 (calcite), it is possible to overestimate or underestimate the growth temperature by small but significant amounts. Increases in salinity lower the clumped crossover pH and may cause larger effects. Extreme effects of pH, salinity, and temperature, such as between cold freshwater lakes at high latitudes to hot hypersaline environments, are predicted to have sizeable effects on the clumped isotope composition of aqueous DIC pools.In order to determine the most reliable and efficient modeling methods to represent aqueous dissolved inorganic carbon (DIC) species and carbonate minerals, we performed convergence and sensitivity testing on several different levels of theory. We used 4 different techniques for modeling the hydration of DIC: gas phase, implicit solvation (PCM and SMD), explicit solvation (ion with 3 water molecules) and supermolecular clusters (ion plus 21 to 32 water molecules with geometries generated by molecular dynamics). For each solvation technique, we performed sensitivity testing by combining different levels of theory (up to 8 ab initio/hybrid methods, each with up to 5 different sizes of basis sets) to understand the limits of each technique. We looked at the degree of convergence with the most complex (and accurate) models in order to select the most reliable and efficient modeling methods. The B3LYP method combined with the 6-311++G(2d,2p) basis set with supermolecular clusters worked well.

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Section: A22 Comparison Of Measured and Model Co 2 (G) Vibrationalmentioning

confidence: 99%

Theoretical constraints on the effects of pH, salinity, and temperature on clumped isotope signatures of dissolved inorganic carbon species and precipitating carbonate minerals

Hill

Tripati

Schauble

2014

Geochimica et Cosmochimica Acta

146

194

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“…The initial sets of the EH parameters were obtained by isotopic extrapolation of that of the principal isotopologue [27]. The weighted fits were performed taking into account of the claimed uncertainties of the line position determination in the respective references.…”

Section: Global Fitting Of the Line Positionsmentioning

confidence: 99%

High sensitivity Cavity Ring Down spectroscopy of 18O enriched carbon dioxide between 5850 and 7000 cm−1: Part III–Analysis and theoretical modeling of the 12C17O2, 16O12C17O, 17O12C18O, 16O13C17O and 17O13C18O spectra

Karlovets

Campargue

Mondelain

et al. 2014

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…These data were mainly derived using the DND (Direct Numerical Diagonalization) method (Watson and Rothman, 1992). However, more recently an analogous method based on global fits of observed frequencies and line intensities using the effective operator approach (Tashkun et al, 1998(Tashkun et al, , 1999a was developed and used to generate new line parameters for the four most abundant isotopic species of carbon dioxide. These frequencies and intensities are available through the Carbon Dioxide Spectroscopic Databank (CDSD) (Tashkun et al, 1999b;Perevalov and Tashkun, 2008).…”

Section: Carbon Dioxidementioning

confidence: 99%

Performance of the line-by-line radiative transfer model (LBLRTM) for temperature and species retrievals: IASI case studies from JAIVEx

et al. 2009

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Abstract. Presented here are comparisons between the Infrared Atmospheric Sounding instrument (IASI) and the "Line-By-Line Radiative Transfer Model" (LBLRTM). Spectral residuals from radiance closure studies during the IASI JAIVEx validation campaign provide insight into a number of spectroscopy issues relevant to remote sounding of temperature, water vapor and trace gases from IASI. In order to perform quality IASI trace gas retrievals, the temperature and water vapor fields must be retrieved as accurately as possible. In general, the residuals in the CO 2 ν 2 region are of the order of the IASI instrument noise. However, outstanding issues with the CO 2 spectral regions remain. There is a large residual ∼−1.7 K in the 667 cm −1 Qbranch, and residuals in the CO 2 ν 2 and N 2 O/CO 2 ν 3 spectral regions that sample the troposphere are inconsistent, with the N 2 O/CO 2 ν 3 region being too negative (warmer) by ∼0.7 K. Residuals on this lower wavenumber side of the CO 2 ν 3 band will be improved by line parameter updates, while future efforts to reduce the residuals reaching ∼−0.5 K on the higher wavenumber side of the CO 2 ν 3 band will focus on addressing limitations in the modeling of the CO 2 line shape (line coupling and duration of collision) effects. Brightness temperature residuals from the radiance closure studies in the ν 2 water vapor band have standard deviations of ∼0.2-0.3 K with some large peak residuals reaching ±0.5-1.0 K. These are larger than the instrument noise indicating that systematic errors still remain. New H 2 O line intensities and positionsCorrespondence to: M. W. Shephard (mshephar@aer.com) have a significant impact on the retrieved water vapor, particularly in the upper troposphere where the water vapor retrievals are 10% drier when using line intensities compared with HITRAN 2004. In addition to O 3 , CH 4 , and CO, of the IASI instrument combined with an accurate forward model allows for the detection of minor species with weak atmospheric signatures in the nadir radiances, such as HNO 3 and OCS.

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Global Fitting of 12c16o2 Vibrational–rotational Line Positions Using the Effective Hamiltonian Approach

Cited by 113 publications

References 0 publications

Theoretical constraints on the effects of pH, salinity, and temperature on clumped isotope signatures of dissolved inorganic carbon species and precipitating carbonate minerals

Theoretical constraints on the effects of pH, salinity, and temperature on clumped isotope signatures of dissolved inorganic carbon species and precipitating carbonate minerals

High sensitivity Cavity Ring Down spectroscopy of 18O enriched carbon dioxide between 5850 and 7000 cm−1: Part III–Analysis and theoretical modeling of the 12C17O2, 16O12C17O, 17O12C18O, 16O13C17O and 17O13C18O spectra

Performance of the line-by-line radiative transfer model (LBLRTM) for temperature and species retrievals: IASI case studies from JAIVEx

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