gill_1963#
P. Gill and D. W. O. Heddle, J. Opt. Soc. Am. 53, 847 (1963)
Source record · Catalogue · Review register
Source kind: measurement
Recorded technique: Rayleigh scattering at 90 degrees of the hydrogen Lyman-alpha line (a 30 Mc/s discharge lamp viewed through LiF; no oxygen filter), iodine-helium photon counter for the scattered light, nitric-oxide ionization chamber monitoring the incident beam; the slope of scattered/incident signal against pressure (to 1 atm) per gas, normalised to argon each day.
Materials in structured entries: Ar, H2, He, Kr, N2, Xe
Dataset quantities: refractivity, refractivity_ratio
Contents: 9 datasets; 0 formulas.
Curation notes#
The measured quantity is the ratio of scattering slopes, which gives (n0 - 1)_i^2 / (n0 - 1)_Ar^2 after the depolarisation correction (Eq. (8)); Table I prints its square root, the ratio of |n0 - 1|. The absolute scale is set by ‘the value of 5.71 x 10^-4 found for nitrogen at 1220 A by the Cerenkov method’ (Heddle et al. 1963), applied at 1216 A (p. 4). n0 - 1 refers to STP by Eq. (3), (n - 1) = (n0 - 1) p (273/T): an ideal-gas scaling (density ‘ideal’). Depolarisation ratios from the visible (N2 0.036; H2 the mean of 0.012 and 0.016). Uncertainty (p. 4): ‘the refractivities of argon, hydrogen, and nitrogen are believed to be correct to better than 2 %’. Krypton and xenon: their resonance lines lie in the counter’s band, so source emission near them would inflate the scattering; ‘it is probably as well to regard the results for krypton and xenon as preliminary measurements’, and ‘the refractivity of krypton is almost certainly negative and so also may be that of xenon’ (hence the modulus bars). Kingston 1964 finds both far too high (Kr would need f about 1.5 for its first resonance line); Leonard 1974 omits all scattering values near resonances; Mahon et al. 1979 show Kr’s n - 1 is negative at 1216 A. The Kr and Xe values are therefore excluded. Table I is internally consistent (ratio = sqrt(S’ x depolarisation factor), absolute = ratio x 5.653) except for krypton, whose printed 53.1 is 0.7 % below 9.46 x 5.653 = 53.5 (unexplained; excluded anyway).
Helium and neon gave no measurable scattering (p. 4); the calculated helium value the paper quotes is recorded as a reproduction. The library PDF also contains an unrelated paper (Patterson and Vaughan, LiF transmission), from p. 5.
Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
gill_1963/absolute_Ar#
{
"id": "absolute_Ar",
"material": "Ar",
"file": "Ar/gill_1963__absolute_Ar.csv",
"table": "tbl_8bd54abf02ad",
"quantity": "refractivity",
"scale": 0.0001,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "ideal",
"use": "primary",
"uncertainty": {
"relative": 0.02,
"level": "bound"
}
}
Table I, |n0 - 1| x 10^4 at 1216 A (Lyman alpha): nitrogen’s Cerenkov value divided by the measured N2/Ar ratio (1.01); agrees with Heddle et al.’s Cerenkov 5.59e-4 at 1210 +- 30 A. Positive (argon’s resonance lines lie at longer wavelength). Gordon et al. 1993 call it ‘much too high’ against Chashchina et al.’s 5.016 and their own calculation, 5.12.
gill_1963/absolute_H2#
{
"id": "absolute_H2",
"material": "H2",
"file": "H2/gill_1963__absolute_H2.csv",
"table": "tbl_8bd54abf02ad",
"quantity": "refractivity",
"scale": 0.0001,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "ideal",
"use": "primary",
"uncertainty": {
"relative": 0.02,
"level": "bound"
}
}
Table I, |n0 - 1| x 10^4 of hydrogen at 1216 A, depolarisation factor 0.975. Gordon et al. 1993 calculate 3.24.
gill_1963/absolute_N2#
{
"id": "absolute_N2",
"material": "N2",
"file": "N2/gill_1963__absolute_N2.csv",
"table": "tbl_8bd54abf02ad",
"quantity": "refractivity",
"scale": 0.0001,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "unknown",
"use": "reproduced",
"reproduced_from": [
"heddle_1963"
]
}
Table I, nitrogen: not a measurement of this paper but the normalising value, Heddle et al.’s Cerenkov result at 1220 +- 30 A (57.1 +- 1.0 x 10^-5), applied at 1216 A.
gill_1963/absolute_Kr#
{
"id": "absolute_Kr",
"material": "Kr",
"file": "Kr/gill_1963__absolute_Kr.csv",
"table": "tbl_8bd54abf02ad",
"quantity": "refractivity",
"scale": 0.0001,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "ideal",
"use": "excluded"
}
Table I, |n0 - 1| x 10^4 = 53.1: a magnitude only (the sign is ‘almost certainly negative’, p. 4), ‘preliminary’, and far too large by Kingston’s (1964) and Mahon et al.’s (1979) analyses (Mahon et al.: n - 1 = -7.75e-24 N at 1215.67 A, about -2.1e-4 at STP). Kept for the record only; the positive number stored here is not a valid refractivity.
gill_1963/ratio_Kr#
{
"id": "ratio_Kr",
"material": "Kr",
"file": "Kr/gill_1963__ratio_Kr.csv",
"table": "tbl_8bd54abf02ad",
"quantity": "refractivity_ratio",
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"use": "excluded",
"parameters": {
"reference_material": "Ar"
}
}
Table I, |n0 - 1|_Kr / |n0 - 1|_Ar = 9.46 at 1216 A: a ratio of magnitudes; excluded for the reasons given for absolute_Kr.
gill_1963/ratio_Xe#
{
"id": "ratio_Xe",
"material": "Xe",
"file": "Xe/gill_1963__ratio_Xe.csv",
"table": "tbl_8bd54abf02ad",
"quantity": "refractivity_ratio",
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"use": "excluded",
"parameters": {
"reference_material": "Ar"
}
}
Table I, |n0 - 1|_Xe / |n0 - 1|_Ar = 30.5 at 1216 A (|n0 - 1| = 172e-4; that absolute value is not extracted, see the extraction script). ‘Preliminary’, sign undetermined; Kingston 1964 shows it would need a discrete oscillator-strength sum of about 5; Mahon et al. 1979 attribute such scattering to Xe2 molecules or fluorescence. Excluded.
gill_1963/ratio_H2#
{
"id": "ratio_H2",
"material": "H2",
"file": "H2/gill_1963__ratio_H2.csv",
"table": "tbl_8bd54abf02ad",
"quantity": "refractivity_ratio",
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"use": "check",
"parameters": {
"reference_material": "Ar"
}
}
Table I, |n0 - 1|_H2 / |n0 - 1|_Ar = 0.57 at 1216 A, the measured quantity behind absolute_H2 (which is this ratio times argon’s value): a check, not fitted beside it.
gill_1963/ratio_N2#
{
"id": "ratio_N2",
"material": "N2",
"file": "N2/gill_1963__ratio_N2.csv",
"table": "tbl_8bd54abf02ad",
"quantity": "refractivity_ratio",
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"use": "check",
"parameters": {
"reference_material": "Ar"
}
}
Table I, |n0 - 1|_N2 / |n0 - 1|_Ar = 1.01 at 1216 A (sqrt(1.10 x 0.925) = 1.009), the ratio that turns the N2 normalisation into absolute_Ar: a check. Leonard 1974 reproduces it as 1.005 +- .01.
gill_1963/dalgarno_stewart_He#
{
"id": "dalgarno_stewart_He",
"material": "He",
"table": "text",
"quantity": "refractivity",
"scale": 1e-05,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"state": "1atm_0C",
"density": "unknown",
"use": "reproduced",
"reproduced_from": [
"A. Dalgarno and A. C. Stewart, Proc. Phys. Soc. (London) 75, 49 (1960)"
]
}
1 inline points in the source record.
p. 4: ‘In the case of helium the refractivity at 1216 A can be reliably calculated from the oscillator strengths obtained by Dalgarno and Stewart to be 4.27 x 10^-5’. A calculated value; the original is not in the library.
Formulas#
No formulas are recorded.
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.