ityaksov_2008_co2#
D. Ityaksov, H. Linnartz and W. Ubachs, Chem. Phys. Lett. 462, 31 (2008)
Source record · Catalogue · Review register
DOI: 10.1016/j.cplett.2008.07.049
Source kind: measurement
Recorded technique: Cavity ring-down extinction with pressure ramps from 0 to 10^5 Pa at room temperature (pressure to 0.15 %), laser bandwidth below 0.2 cm^-1; 40 cm cell for 215-270 nm, the 82 cm turbulence-free cell for 198-204 nm (pp. 2-3). CO2 99.7 %.
Materials in structured entries: CO2
Dataset quantities: rayleigh_cross_section
Contents: 2 datasets; 3 formulas.
Curation notes#
CO2 was deferred when this record was written (every dataset “check”); the CO2 was taken up on 2026-09-25, so the measured extinction is primary like any other gas’s data (the calculated column stays a check).
The measured quantity is the extinction cross section per molecule, Rayleigh scattering plus absorption; below about 202 nm CO2 absorbs (‘the onset actually starts at higher energy, around 202 nm’, abstract), and the paper’s Rayleigh fit is restricted to 202-300 nm. The rows below 202 nm are therefore excluded from the Rayleigh dataset (kept in its file). ‘The experimental error (1 sigma uncertainty) is ~15% for the measurements in the 215.38-270.15 nm interval and about 10% for observations in the wavelength region where the turbulence free CRD cell has been used’ (p. 2); the table’s +- are the per-point one-sigma values. No quadratic density dependence (collision-induced effects) was found. Wavelengths are vacuum (Eqs. 3-4, ‘the wavelength lambda (in vacuum)’).
The calculated cross sections use Eq. (2) with ‘the dispersion formulas for the refractive indices [9] and depolarization ratios [10]’ at 288.15 K and 101 325 Pa. Check (2026-09-25): with N = 2.5469e19 cm^-3, the refractive-index formula of sneep_2005 (Eq. 13, scale read as 1.1427 x 10^3) and its King factor (Eq. 14, 1.1364 + 25.3e-12 nu^2) every one of the 22 calculated values is reproduced to its printed 0.1; with this paper’s rounded Eqs. (3) and (4) they come out up to 0.08 higher. Eq. (4) repeats sneep_2005’s misprinted scale 1.1427 x 10^6 (it must be 10^3).
The literature data of Figs. 1-3 (Shemansky, Ogawa, Karaiskou et al., Parkinson et al., Lewis and Carver, Sneep et al., Dong and Gupta) are not tabulated here.
Recorded bibliographic identity status: VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
ityaksov_2008_co2/extinction_CO2#
{
"id": "extinction_CO2",
"material": "CO2",
"file": "CO2/ityaksov_2008_co2__extinction_CO2.csv",
"table": "tbl_d53eeed0ae27",
"quantity": "rayleigh_cross_section",
"unit": "cm2",
"scale": 1e-25,
"abscissa_unit": "nm",
"wavelength_medium": "vacuum",
"use": "primary",
"excluded_rows": {
"197.70": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"197.84": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"198.28": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"198.38": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"198.48": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"198.75": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"199.10": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"199.55": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"199.90": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"200.08": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"200.42": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"200.76": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"201.00": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"201.33": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"201.58": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption",
"201.78": "below the absorption onset near 202 nm: the extinction includes CO2 photoabsorption"
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table 1, measured extinction cross section, +- one sigma. Rows from 202.43 nm on are Rayleigh scattering (the paper’s fit range 202-300 nm); 201.78 nm (8.0 +- 1.2) lies below the calculated 9.1 and is excluded with the absorbing rows by the paper’s onset. Deferred gas: check.
ityaksov_2008_co2/calculated_CO2#
{
"id": "calculated_CO2",
"material": "CO2",
"file": "CO2/ityaksov_2008_co2__calculated_CO2.csv",
"table": "tbl_d53eeed0ae27",
"quantity": "rayleigh_cross_section",
"unit": "cm2",
"scale": 1e-25,
"abscissa_unit": "nm",
"wavelength_medium": "vacuum",
"use": "check"
}
Table 1, sigma_R^calc from Bideau-Mehu et al.’s refractive index and Alms et al.’s depolarization (via sneep_2005’s Eqs. 13 and 14; see the source notes). Not a measurement.
Formulas#
ityaksov_2008_co2/king_eq3#
{
"id": "king_eq3",
"material": "CO2",
"equation": "Eq. (3), p. 2",
"printed": "F_k(lambda) = 1.14 + 25.3 x 10^-12 / lambda^2",
"variable": "lambda: vacuum wavelength in cm",
"range": "not stated (sneep_2005's fit to Alms et al., 4579-6471 A)",
"coefficients": {
"a": "1.14",
"b": "25.3e-12"
},
"reproduced_from": [
"sneep_2005"
],
"check": "sneep_2005's Eq. (14) with 1.1364 rounded to 1.14; the calculated column follows the unrounded form (see the source notes). Checked 2026-09-25."
}
ityaksov_2008_co2/n_eq4#
{
"id": "n_eq4",
"material": "CO2",
"equation": "Eq. (4), p. 2",
"printed": "n(lambda) - 1 = 1.1427 x 10^6 (5799.3 lambda^2/(16.6 x 10^9 lambda^2 - 1) + 120 lambda^2/(7.96 x 10^9 lambda^2 - 1) + 5.33 lambda^2/(5.63 x 10^9 lambda^2 - 1) + 4.32 lambda^2/(4.6 x 10^9 lambda^2 - 1) + 1.22 x 10^-5 lambda^2/(5.85 x 10^6 lambda^2 - 1))",
"variable": "lambda: vacuum wavelength in cm",
"state": "1atm_15C",
"density": "ideal",
"range": "180-254 nm (Bideau-Mehu et al.'s data, as stated p. 3)",
"coefficients": {
"scale": "1.1427e6",
"B1": "5799.3",
"C1": "16.6e9",
"B2": "120",
"C2": "7.96e9",
"B3": "5.33",
"C3": "5.63e9",
"B4": "4.32",
"C4": "4.6e9",
"B5": "1.22e-5",
"C5": "5.85e6"
},
"reproduced_from": [
"sneep_2005",
"A. Bideau-Mehu, Y. Guern, R. Abjean and A. Johannin-Gilles, Opt. Commun. 9, 432 (1973)"
],
"check": "sneep_2005's Eq. (13) rewritten with the poles squared and rounded (128908.9^2 = 1.6617e10 -> 16.6e9, ...). The scale 1.1427 x 10^6 gives n - 1 = 0.5 at 200 nm; with 10^3, 501.7e-6 at 197.7 nm. Checked 2026-09-25."
}
ityaksov_2008_co2/power_eq6#
{
"id": "power_eq6",
"material": "CO2",
"equation": "Eq. (6), p. 3",
"printed": "sigma_R = sigma_bar nu^(4 + epsilon); sigma_bar = 1.78(7) x 10^-46, epsilon = 0.625(3)",
"variable": "nu: vacuum wavenumber in cm^-1; sigma_R in cm^2",
"range": "202-300 nm (fitted to this work's and the literature's data except Ogawa's); 'not meant to be extrapolated beyond 300 nm', 20 % off at 532 nm",
"coefficients": {
"sigma_bar": "1.78e-46",
"epsilon": "0.625"
},
"check": "Gives 9.10, 6.83, 2.39 x 10^-25 cm^2 at 202.43, 215.38, 270.15 nm against the measured 7.9 +- 0.8, 6.6 +- 1.0, 2.3 +- 0.4 and calculated 9.0, 6.7, 2.4. Checked 2026-09-25."
}
Corrections#
No dataset errata are recorded in this source record.
Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.