alms_1975#

G. R. Alms, A. K. Burnham and W. H. Flygare, J. Chem. Phys. 63, 3321 (1975)

Source record · Catalogue · Review register

Source kind: measurement

Recorded technique: Depolarization ratio of Rayleigh-scattered light at 90 degrees from dilute gases (up to 1 atm), argon-ion laser at 4579, 4880, 5145 A and krypton-ion laser at 5682, 6471 A, photon counting (p. 3); depolarization ratios at 6328 A from Bridge and Buckingham (Proc. R. Soc. A 295, 334 (1966)). The mean polarizabilities are not measured here: they are taken from the refractive indices in Landolt-Bornstein (1962), Vol. 2, Pt. 8, p. 871 (Ref. 4) with n - 1 = 2 pi N alpha (Eq. 1).

Materials in structured entries: CO2, N2, N2O

Dataset quantities: polarizability

Contents: 6 datasets; 0 formulas.

Curation notes#

The paper measures the dispersion of the depolarization ratio and so of the polarizability anisotropy; the mean polarizability alpha of Table I (A^3, a polarizability volume) is ‘obtained from refractive index [Eq. (1)] measurements as a function of wavelength listed in the Landolt-Bornstein tables, except for CS2 and 2-butyne’ (p. 3): for the curated gases (N2, N2O, CO2) every alpha is a reproduction of Landolt-Bornstein, whose original measurements are not named. ‘The uncertainties in alpha are 0.5%-2.0% from the smaller to the larger molecules in Table I’ (p. 3). The anisotropies, alpha_parallel and alpha_perp (Tables I, IV, V) are not extracted (left for later), nor the depolarization ratios (Tables I, II), which have no quantity in the vocabulary. The other molecules (OCS, CS2, CH3Cl, CHCl3, HCCH, propyne, 2-butyne, C6H6, CH3CN) are not curated species.

Wavelengths are the laser lines as printed to 1 A (Ar+ 4579, 4880, 5145; Kr+ 5682, 6471; He-Ne 6328), air wavelengths: recorded as standard air.

The ‘inf’ row of each molecule is the zero-frequency value: for alpha, the paper does not say how it was extrapolated. It is the electronic polarizability only: ‘the resultant extrapolation to zero frequency ... [does] not include the vibrational contribution’ (p. 6), so for N2O and CO2 it is not the static polarizability. The row is excluded from the datasets.

Table III lists band oscillator strengths (N2 958 A, CO2 1121 A, N2O 1284 A), three times the orientationally averaged experimental values of Lawrence et al. (1968) and Rabalais et al. (1971): reproduced and rescaled, not extracted.

Table V (Stuart 1952) static electronic polarizabilities are extracted as reproduced (excluded) values. They are ‘derived variously from light scattering, Kerr, refractive index, and dielectric measurements’ and ‘in many cases they differ by as much as 10% from our determinations’ (p. 7).

The library holds a second copy, Alms_1975_MeasurementDispersionPolarizability_b51bf6 (same DOI): its text is identical but for figure ids and machine descriptions, and its Table I cells are identical; it is not extracted twice.

Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets#

alms_1975/alpha_N2#

{
  "id": "alpha_N2",
  "material": "N2",
  "file": "N2/alms_1975__alpha_N2.csv",
  "table": "tbl_24841f218204",
  "quantity": "polarizability",
  "unit": "angstrom3",
  "abscissa_unit": "angstrom",
  "wavelength_medium": "standard_air",
  "use": "reproduced",
  "reproduced_from": [
    "Landolt-Bornstein, Zahlenwerte und Funktionen (Springer, Berlin, 1962), Vol. 2, Pt. 8, p. 871"
  ],
  "excluded_rows": {
    "inf": "zero-frequency extrapolation of the optical values (electronic only; method not stated)"
  },
  "uncertainty": {
    "relative": 0.005,
    "level": "not stated"
  }
}

Table I, alpha column; the last digit is printed as a subscript (a guard digit). The 5148 A row is the 5145 A argon-ion line (erratum). The 6328 A depolarization ratio is Bridge and Buckingham’s; the alpha is Landolt-Bornstein’s like the others. Uncertainty: 0.5 %, the paper’s value for ‘the smaller’ molecules (p. 3).

alms_1975/alpha_N2O#

{
  "id": "alpha_N2O",
  "material": "N2O",
  "file": "N2O/alms_1975__alpha_N2O.csv",
  "table": "tbl_24841f218204",
  "quantity": "polarizability",
  "unit": "angstrom3",
  "abscissa_unit": "angstrom",
  "wavelength_medium": "standard_air",
  "use": "reproduced",
  "reproduced_from": [
    "Landolt-Bornstein, Zahlenwerte und Funktionen (Springer, Berlin, 1962), Vol. 2, Pt. 8, p. 871"
  ],
  "excluded_rows": {
    "inf": "zero-frequency extrapolation of the optical values (electronic only, without the vibrational part; method not stated)"
  },
  "uncertainty": {
    "relative": 0.02,
    "level": "bound"
  }
}

Table I, alpha column. Uncertainty: the paper’s range 0.5-2.0 % (p. 3), its upper end taken as a bound.

alms_1975/alpha_CO2#

{
  "id": "alpha_CO2",
  "material": "CO2",
  "file": "CO2/alms_1975__alpha_CO2.csv",
  "table": "tbl_24841f218204",
  "quantity": "polarizability",
  "unit": "angstrom3",
  "abscissa_unit": "angstrom",
  "wavelength_medium": "standard_air",
  "use": "reproduced",
  "reproduced_from": [
    "Landolt-Bornstein, Zahlenwerte und Funktionen (Springer, Berlin, 1962), Vol. 2, Pt. 8, p. 871"
  ],
  "excluded_rows": {
    "inf": "zero-frequency extrapolation of the optical values (electronic only, without the vibrational part; method not stated)"
  },
  "uncertainty": {
    "relative": 0.02,
    "level": "bound"
  }
}

Table I, alpha column. Uncertainty: the paper’s range 0.5-2.0 % (p. 3), its upper end taken as a bound.

alms_1975/stuart_alpha_N2#

{
  "id": "stuart_alpha_N2",
  "material": "N2",
  "file": "N2/alms_1975__stuart_alpha_N2.csv",
  "table": "tbl_e60dab9bc511",
  "quantity": "polarizability",
  "unit": "angstrom3",
  "abscissa_unit": "angstrom",
  "use": "excluded",
  "reproduced_from": [
    "H. A. Stuart, Die Struktur des freien Molekuls (Springer, Berlin, 1952)"
  ]
}

Table V, Stuart’s zero-frequency electronic mean polarizability (before the parenthesis). Excluded: a compiled value of mixed origin, electronic only (no vibrational part), with no stated uncertainty or method.

alms_1975/stuart_alpha_N2O#

{
  "id": "stuart_alpha_N2O",
  "material": "N2O",
  "file": "N2O/alms_1975__stuart_alpha_N2O.csv",
  "table": "tbl_e60dab9bc511",
  "quantity": "polarizability",
  "unit": "angstrom3",
  "abscissa_unit": "angstrom",
  "use": "excluded",
  "reproduced_from": [
    "H. A. Stuart, Die Struktur des freien Molekuls (Springer, Berlin, 1952)"
  ]
}

Table V, as stuart_alpha_N2.

alms_1975/stuart_alpha_CO2#

{
  "id": "stuart_alpha_CO2",
  "material": "CO2",
  "file": "CO2/alms_1975__stuart_alpha_CO2.csv",
  "table": "tbl_e60dab9bc511",
  "quantity": "polarizability",
  "unit": "angstrom3",
  "abscissa_unit": "angstrom",
  "use": "excluded",
  "reproduced_from": [
    "H. A. Stuart, Die Struktur des freien Molekuls (Springer, Berlin, 1952)"
  ]
}

Table V, as stuart_alpha_N2.

Formulas#

No formulas are recorded.

Corrections#

[
  {
    "dataset": "alpha_N2",
    "row": "5148",
    "column": "x",
    "printed": "5148",
    "corrected": "5145",
    "reason": "The argon-ion line used is 5145 A (p. 3, 'Depolarization ratios were measured at 4579, 4880, and 5145 A'); every other molecule of Table I prints 5145 in that row.",
    "evidence": "Table I image checked: nitrogen's row reads 5148. The 3 A difference changes the Landolt-Bornstein alpha by about 4e-5 A^3 (not 4e-4, (second reading, 2026-09-25; TC-157)), below its printed precision."
  }
]

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.