watanabe_1952#
K. Watanabe, E. C. Y. Inn and M. Zelikoff, “Absorption coefficients of gases in the vacuum ultraviolet”, J. Chem. Phys. 20, 1969 (1952)
Source record · Catalogue · Review register
DOI: 10.1063/1.1700353
Source kind: measurement
Recorded technique: Photoelectric absorption (letter): a Baird 1 m vacuum monochromator (exit slit 0.05 mm, band width 0.85 A), an H2 discharge source, an absorption cell with LiF windows between the exit slit and a sodium-salicylate-coated 1P21 photomultiplier; repeated measurements with the cell empty and filled against the source drifts (+-5 percent); 1050-2500 A (p. 1969).
Materials in structured entries: CO2, O2
Dataset quantities: absorption_cross_section
Contents: 4 datasets; 0 formulas.
Curation notes#
Journal pages 1969-1970 = PDF pages 2-3 (page 1 is the publisher’s cover; the letter starts at the foot of the first column of p. 1969, after the end of another letter). Identity checked against the page image (pdf 2): Watanabe, Inn and Zelikoff, ‘Absorption Coefficients of Gases in the Vacuum Ultraviolet’, J. Chem. Phys. 20, 1969 (1952), received 13 October 1952, a letter to the editor with no part number. It is the preliminary communication of the series, not its Part I: Part III (inn_1953) refers to ‘Part I of this series’ for the method, which is the O2 paper (watanabe_1953, J. Chem. Phys. 21, 1026 (1953)); Part II is zelikoff_1953 (N2O). The library’s OCR of this page is poor (‘10SQ-2S00A’, ‘14S0A’); the values below were read from the page images.
Gases: O2 (Fig. 1, 1200-1550 A, log scale, with Ladenburg and Van Voorhis’s curve L-V) and CO2 (text only); ‘several gases’ are announced for a fuller report. Quantity: k in cm^-1 ‘base e’; the reference state is not stated in the letter: NTP (0 C, 1 atm) as in the full papers of the series (watanabe_1953, zelikoff_1953, inn_1953) is assumed, and the datasets store k with scale = 1e18 / n0, n0 = 2.6867801e19 cm^-3 (ideal gas), to Mb, as watanabe_1953 and inn_1953. Temperature not stated. No accuracy statement beyond the source drifts (+-5 percent).
O2 text (p. 1969): the Schumann-Runge continuum maximum 380 cm^-1 at 1420 A, ‘in contrast to the accepted value of about 490 cm^-1 at 1450A obtained by Ladenburg and van Voorhis’ (ladenburg_1933), and a more asymmetric distribution; narrow continua or diffuse bands D, E, F at about 1352, 1330 and 1293 A (reported by Tanaka) and very diffuse bands A, B, C below 1270 A (positions only, figure). These are the same measurements that watanabe_1953 reports in full (380 cm^-1 at about 1420 A there too): the O2 datasets here are checks, not independent. At Lyman alpha 0.33 cm^-1, ‘in good agreement with the value 0.315 cm^-1 found by Preston for a corresponding pressure (7.5 cm Hg)’ (pressure-dependent; watanabe_1953 extrapolates 0.27 cm^-1 to zero pressure). Ditchburn and Heddle (ditchburn_1953, p. 69) quote this letter’s maximum as ‘380 cm^-1 at 71000 cm^-1’ and suspect scattered light.
CO2 text (pp. 1969-1970): 2.0 cm^-1 at Lyman alpha (Preston 2.01, reproduced, not extracted); the continuum ‘as much as a factor two greater’ than Wilkinson and Johnston’s in 1450-1700 A, nearly forty diffuse bands on a continuum extending to about 1200 A (Wilkinson and Johnston’s bands at 1662, 1673, 1690 A), and ‘at least two maxima of about 14 cm^-1 and 18.5 cm^-1 at 1475A and 1335A’. The full CO2 paper (inn_1953) gives 1.97 cm^-1 at Lyman alpha and the continua maxima at about 1475, 1332 and 1121 A but their k only in figures: the two maxima here are the only printed values.
Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
watanabe_1952/o2_sr_maximum#
{
"id": "o2_sr_maximum",
"material": "O2",
"table": "text",
"quantity": "absorption_cross_section",
"unit": "Mb",
"scale": 0.03721927208,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"use": "check"
}
1 inline points in the source record.
p. 1969: ‘the maximum coefficient of the Schumann-Runge continuum of O2 was found to be 380 cm^-1 (base e) at 1420A’. scale = 1e18 / n0 (NTP assumed) to Mb. The preliminary report of the measurement published in full as watanabe_1953 (sr_maximum, the same 380 cm^-1): a check, not fitted beside it. Uncertainty not stated.
watanabe_1952/o2_lyman_alpha#
{
"id": "o2_lyman_alpha",
"material": "O2",
"table": "text",
"quantity": "absorption_cross_section",
"unit": "Mb",
"scale": 0.03721927208,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"use": "excluded"
}
1 inline points in the source record.
p. 1969: ‘At Lyman alpha, the absorption coefficient was 0.33 cm^-1’, compared with Preston’s 0.315 cm^-1 ‘for a corresponding pressure (7.5 cm Hg)’. Excluded: a pressure-dependent value at about 75 mm Hg in a window between bands; watanabe_1953 gives 0.30 at 70 mm and the zero-pressure 0.27 cm^-1 (its lyman_alpha dataset). The letter names the line only; 1215.7 A as in watanabe_1953 (from metzger_1964 Table 1).
watanabe_1952/co2_lyman_alpha#
{
"id": "co2_lyman_alpha",
"material": "CO2",
"table": "text",
"quantity": "absorption_cross_section",
"unit": "Mb",
"scale": 0.03721927208,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"use": "check"
}
1 inline points in the source record.
p. 1969: ‘Our result (2.0 cm^-1) for CO2 at Lyman alpha also agrees with his carefully determined value (2.01 cm^-1)’ (Preston’s). scale = 1e18 / n0 (NTP assumed) to Mb. The full paper inn_1953 gives 1.97 cm^-1 at 1216 A (its lyman_alpha, primary): this preliminary value is a check. The letter names the line only; 1215.7 A as in watanabe_1953.
watanabe_1952/co2_continuum_maxima#
{
"id": "co2_continuum_maxima",
"material": "CO2",
"table": "text",
"quantity": "absorption_cross_section",
"unit": "Mb",
"scale": 0.03721927208,
"abscissa_unit": "angstrom",
"wavelength_medium": "vacuum",
"use": "primary"
}
2 inline points in the source record.
p. 1970: ‘The continuum itself has at least two maxima of about 14 cm^-1 and 18.5 cm^-1 at 1475A and 1335A, respectively’ (the continuum under the diffuse bands). scale = 1e18 / n0 (NTP assumed) to Mb. Approximate (‘about’); uncertainty not stated. The same group’s full CO2 paper (inn_1953) places the maxima at about 1475 and 1332 A but gives k only in figures, so these are the only printed values: primary, preliminary (to confirm against inn_1953’s Fig. 1).
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.