metzger_1964
============

P\. H\. Metzger and G\. R\. Cook, "A reinvestigation of the absorption cross\-sections of molecular oxygen in the 1050\-1800 A region", J\. Quant\. Spectrosc\. Radiat\. Transfer 4, 107 \(1964\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/metzger_1964.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1016/0022\-4073\(64\)90057\-3 <https://doi.org/10.1016/0022-4073%2864%2990057-3>`__

**Source kind:** measurement

**Recorded technique:** Photoelectric absorption with a McPherson 1 m Seya/normal\-incidence vacuum monochromator \(three gratings, blazed near 1200 A\), bandwidth about 0\.5 A \(0\.050 x 12\.5 mm slits\); two sources, a hydrogen discharge \(many\-line spectrum 850\-1650 A, continuum above 1650 A\) and a condensed\-discharge argon continuum \(1050\-1600 A\); the absorption cell behind the exit slit \(LiF windows or the stainless\-steel chamber, three detector arrangements, scattered light varied from under 0\.5 % to 40 % and corrected\); pressure by a cold\-trapped McLeod gauge; O2 of three samples, N2 under 0\.01 % \(pp\. 107\-112\)\. Windows measured with an 85\.9 cm path \(p\. 112\)\. Each value in 1300\-1675 A a least\-squares fit of transmission against pressure \(p\. 113\)\.

**Materials in structured entries:** O2

**Dataset quantities:** absorption\_cross\_section, oscillator\_strength

**Contents:** 3 datasets; 0 formulas.

Curation notes
--------------

Journal pages 107\-116 = PDF pages 1\-10\. O2 only\. Wavelengths in A, vacuum ultraviolet \(vacuum wavelengths\)\.

Quantity \(p\. 108\)\: phi = phi0 exp\(\-n sigma L\), sigma = ln\(phi0/phi\)/\(n L\) '= k n0' with 'n0 \.\.\. Loschmidt's number' \(printed so; the numbers show sigma = k / n0\), n0 = 2\.69 x 10^19 molecules/cm^3 \(p\. 115\)\: k is the natural\-log absorption coefficient \(cm^\-1\) at the Loschmidt density\. The dataset keeps the printed k with scale = 1e18 / 2\.69e19 = 0\.037174721 to the cross section in Mb \(the paper's own conversion\: 402 cm^\-1 'corresponds to a total absorption cross section of 1\.49 \+\- 0\.10 x 10^\-17 cm^2', p\. 114, printed garbled as '1\.49 \+\- 1 x 0\.10^\-17'; 402 / 2\.69e19 = 1\.494e\-17\)\. The ideal\-gas n0 at 0 C and 1 atm, 2\.6868e19, is 0\.12 % lower; Fig\. 5's right\-hand scale \(sigma in 10^\-18 cm^2\) follows 2\.687e19 in most of its labels \(figure only\)\. The vocabulary has no photoabsorption cross section\: 'photoionization\_cross\_section' is used \(all of Table 2 lies below the O2 ionisation limit; format need reported\)\. Temperature not stated\.

Accuracy\: the Schumann\-Runge maximum 'near 1422 A is 402 \+\- 20 cm^\-1' \(p\. 114\), the envelope of seven or eight points per wavelength \(Fig\. 6, figure only\); otherwise not stated\. The windows 'satisfy Beer's law'; 'The value of Ly alpha shows a slight pressure effect noted in the data taken at shorter path lengths' \(p\. 112\)\. Band values A, B, C are approximate in Fig\. 2's legend \(A 'k ~ 200', B 'k ~ 430', C 'k ~ 1200'; D, E, F with '='\) \(p\. 109\)\. The dissociation continuum itself \(1300\-1800 A, Figs\. 5\-6, over 100 wavelengths\) is given only in figures\.

Table 2 prints 420 cm^\-1 for the S\-R maximum, against 402 \+\- 20 in the abstract \(p\. 107\), Fig\. 2's legend \('\(S\-R\)MAX 1420 A, k = 402 \+\- 20 cm^\-1', p\. 109\) and the text \(p\. 114\), which also converts 402 to 1\.49e\-17 cm^2 \(erratum\)\. The wavelength of the maximum is 1422 A in Table 2 and the text, 1420 A in Fig\. 2\.

Oscillator strength of the S\-R continuum \(p\. 115\)\: f = \(m c^2 / \(n0 e^2 pi\)\) integral k\(nu\) dnu from nu1 = 5\.71e4 to nu2 = 7\.41e4 cm^\-1 \(n0 = 2\.69e19, e^2/mc^2 = 2\.82e\-13 cm\) 'was found to be f = 0\.142, a value somewhat lower than previously determined values' \(Ladenburg and Van Voorhis 1933, Watanabe et al\. 1953\)\. Comparisons \(pp\. 107\-108\)\: Watanabe et al\.'s maximum at 1420 A about 25 % below Ditchburn and Heddle's 490 cm^\-1 at 1450 A; this work agrees with Watanabe et al\. 'within experimental error' \(p\. 114\)\.

Table 1 \(impurity emission lines of the argon source with relative intensities\) is not data\. Reference 7 \(Watanabe, Advances in Geophysics 5, 157 \(1958\)\) is cited as 'A more complete listing of absorption coefficients' \(not in the library\)\.

**Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets
--------

metzger\_1964/bands\_windows
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "bands_windows",
     "material": "O2",
     "file": "O2/metzger_1964__bands_windows.csv",
     "table": "tbl_cbf80ad2566e",
     "quantity": "absorption_cross_section",
     "unit": "Mb",
     "scale": 0.03717472119,
     "abscissa_unit": "angstrom",
     "wavelength_medium": "vacuum",
     "use": "primary"
   }

Table 2\: k \(cm^\-1\) of the diffuse bands A\-F \(peak values; A\-C approximate\) and the seven windows 1\-7 \(85\.9 cm path; window 1 is Lyman alpha, 1215\.7 A\); scale = 1e18 / 2\.69e19 \(the paper's n0\) to the cross section in Mb\. Uncertainty not stated\. Resolution about 0\.5 A\. The windows are narrow minima between bands\: their values depend on the wavelength setting and the band width\.

metzger\_1964/sr\_maximum
~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "sr_maximum",
     "material": "O2",
     "file": "O2/metzger_1964__sr_maximum.csv",
     "table": "tbl_cbf80ad2566e",
     "quantity": "absorption_cross_section",
     "unit": "Mb",
     "scale": 0.03717472119,
     "abscissa_unit": "angstrom",
     "wavelength_medium": "vacuum",
     "use": "primary",
     "uncertainty": {
       "relative": 0.05,
       "level": "not stated"
     }
   }

Table 2 last row\: the maximum of the Schumann\-Runge continuum, 1422 A; printed 420 cm^\-1, corrected to the 402 \+\- 20 cm^\-1 of the abstract, Fig\. 2 and the text \(erratum\); \+\-20 cm^\-1 = 5 % \(level not stated\)\. scale = 1e18 / 2\.69e19 to Mb \(1\.49e\-17 cm^2 = 14\.9 Mb, as the paper states\)\.

metzger\_1964/sr\_continuum\_f
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "sr_continuum_f",
     "material": "O2",
     "table": "text",
     "quantity": "oscillator_strength",
     "abscissa": "label",
     "use": "check"
   }

1 inline points in the source record.

p\. 115\: the oscillator strength of the Schumann\-Runge continuum B 3Sigma\_u^\- \<\- X 3Sigma\_g^\-, the integral of k\(nu\) over 5\.71e4\-7\.41e4 cm^\-1 \(1750\-1350 A\) with n0 = 2\.69e19 cm^\-3\. Index abscissa\: an integrated strength over the stated range, not a line\. Compare watanabe\_1953 \(0\.161 over 5\.7e4\-7\.8e4 cm^\-1\)\. A check\.

Formulas
--------

No formulas are recorded.

Corrections
-----------

.. code-block:: text

   [
     {
       "dataset": "sr_maximum",
       "row": "S-R maximum",
       "column": "value",
       "printed": "420",
       "corrected": "402",
       "reason": "Table 2 prints 420 cm^-1 for the maximum of the Schumann-Runge continuum; the abstract (p. 107), Fig. 2's legend (p. 109) and the text (p. 114) give 402 +- 20 cm^-1, and the text's cross section 1.49e-17 cm^2 is 402 / 2.69e19 (420 would give 1.56e-17).",
       "evidence": "Table image tbl_cbf80ad2566e.jpg (prints 420) and the pdf pages 3 and 8 (Fig. 2 legend, p. 114 text), checked 2026-09-25."
     }
   ]

Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register </register>` for the checks and decisions.