weissler_1952
=============

G\. L\. Weissler and Po Lee, "Absorption coefficients of oxygen in the vacuum ultraviolet", J\. Opt\. Soc\. Am\. 42, 200 \(1952\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/weissler_1952.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1364/josa\.42\.000200 <https://doi.org/10.1364/josa.42.000200>`__

**Source kind:** measurement

**Recorded technique:** Photographic photometry with a grazing\-incidence vacuum spectrograph filled with O2 at 0\.5\-100 micron \(Hg\) and a line\-emission light source \(lines of O, N, C, Si, H, He ions, some in second and third order\); light path 79\.7 cm at 550 A to 103\.3 cm at 1300 A\. Each k is the slope of ln I against p from at least three, often five, pressures \(Beer's law tested\) \(Eqs\. 1, 1a, pp\. 200\-201\)\. Wavelengths are those of the source lines \(vacuum ultraviolet\: vacuum wavelengths; the printed wave numbers are 1e8/lambda\)\. Resolution\: that of the spectrograph with a line source; not stated\.

**Materials in structured entries:** O2

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

**Contents:** 4 datasets; 1 formula.

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

Journal pages 200\-203 = PDF pages 1\-4\. O2 only; 76 rows between 303\.779 and 1306\.038 A \(the paper's '76 wavelengths' counts the OI 990\.797 line printed twice\)\.

Quantity\: k \(cm^\-1\) is defined by I = I0 exp\(\-k x\), 'x is the thickness of the absorbing gas layer at N\.T\.P\.', reduced with the ideal\-gas law x = T0 L p / \(p0 T\), T0 = 0 C, p0 = atmospheric pressure \(Eq\. 1, pp\. 200\-201\)\: a natural\-log absorption coefficient per unit length at 0 C and 1 atm\. The paper gives no conversion to cross sections\. The datasets store the printed k with scale = 1e18 / n0 \(and x 10^2 for Table I's column factor\), n0 = 101325 Pa / \(k\_B 273\.15 K\) = 2\.6867801e19 cm^\-3 \(the ideal\-gas Loschmidt number from the exact SI constants, matching the paper's ideal\-gas reduction\), giving the photoabsorption cross section per molecule in Mb\. The vocabulary has no photoabsorption cross section\: 'photoionization\_cross\_section' is used, as for the noble gases, although below the first ionisation limit \(about 1027 A\) the absorption is into bands and dissociation continua, not ionisation \(format need reported\)\.

Accuracy \(p\. 202\)\: 'The error in the coefficients presented here is estimated to be about ten percent for k\-values greater than 100 cm^\-1 and fifteen percent for lower values', with the note 'The experiment was not designed to measure k\-values less than 20 cm^\-1 accurately'; slit\-width errors 'within the stated limits'\. 'it is felt that the accuracy of k\-values which fall within molecular absorption bands is less than those within a continuum\. Furthermore, their physical significance is not clear' \(p\. 201\)\: those rows carry a band location \(B\.H\., B\.M\., B\.T\.\) in the printed column; they are not band averages but values at single source lines, partly inside unresolved bands\.

Text values \(pp\. 200\-203, not extracted as data\)\: at 1300 A 'k less than 10 cm^\-1'; between 1300 and 1000 A about 10 cm^\-1 outside bands, 'a weak continuous absorption \.\.\. of the order of k = 50 cm^\-1 to k = 100 cm^\-1' \(p\. 202\); between 1000 and 740 A the lowest value outside a band 110 cm^\-1, in the bands 600 cm^\-1 or more; below 740 A k = 500\-1000 cm^\-1 'with a broad maximum of k = 700 cm^\-1 between 400A and 600A and still being strong at 303A, namely k = 550 cm^\-1' \(p\. 202\)\. The abstract says 530 cm^\-1 at 303A, as Table I \(5\.3 x 10^2 at 303\.779 A\)\: the text's 550 is a misprint of the paper \(no dataset holds it\)\. The dotted curve of Fig\. 1 \(figure only\) joins roughly the lowest k values between 1000 and 300 A\. Reproduced \(p\. 200\)\: Ladenburg and Van Voorhis's Schumann continuum maximum 490 cm^\-1 at about 1450 A\.

Comparison\: Watanabe et al\. \(1953, watanabe\_1953\) found the k of these authors in 1060\-1170 A 'in general, considerably larger' \(attributed to resolution\) and the weak continuum near 1105 A of order 1 cm^\-1, not 50\-100 cm^\-1; Metzger and Cook \(1964, metzger\_1964\) measured windows of k = 0\.20\-0\.62 cm^\-1 at 1108\-1216 A, where this table gives 43\-120 cm^\-1 at nearby lines\. Above 1027 A these values are not reliable between bands\.

Wave\-number and wavelength columns disagree \(1e8/lambda against the printed wave number\) beyond their precision in 14 rows; the wavelength \(the source line\) is used and only row 54 is corrected, where the paper itself gives the evidence \(erratum\)\. Rows \(printed wave number; wavelength implied by it\)\: 4 \(80431\.1; 1243\.30\), 8 \(83364\.8; 1199\.55, italic digit\), 15 \(92201\.7; 1084\.58\), 17 \(96497\.1; 1036\.300\), 18 \(97942\.8 for 97492\.8, a transposition\), 32 \(110667; 903\.611\), 33 \(113815; 878\.62, against 886\.618 printed\), 38 \(120060; 832\.917\), 48 \(142284; 702\.820\), 52 \(148600; 672\.948\), 54 \(151450; 660\.284\: erratum\), 63 \(172177; 580\.797\), 68 \(185499; 539\.086\), 71 \(188900, italic 00; 529\.38\), 74 \(235236 for 232536, a transposition\)\. In bands and windows a wrong wavelength would matter; in the continuum below 740 A it does not\.

Table II's percent differences are not all reproduced by its columns\: 640 and 670 differ by 4\.6 %, printed 7\.8 \(the others agree to 0\.3 %\); not extracted\.

Formula\: Ladenburg and Wolfsohn's three\-term dispersion of O2, quoted p\. 200 \(see formulas\); the paper's integral of its continuum \(p\. 203\) 'a mean oscillator strength of approximately f = 6', against Ladenburg and Wolfsohn's f3 = 5\.9\.

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

Datasets
--------

weissler\_1952/table\_1
~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "table_1",
     "material": "O2",
     "file": "O2/weissler_1952__table_1.csv",
     "table": "tbl_56bc106d3886, tbl_3c7b2b7dceeb",
     "quantity": "absorption_cross_section",
     "unit": "Mb",
     "scale": 3.721927208,
     "abscissa_unit": "angstrom",
     "wavelength_medium": "vacuum",
     "use": "primary",
     "excluded_rows": {
       "1": "k = 7 cm^-1, below the 20 cm^-1 the experiment 'was not designed to measure ... accurately' (p. 202, Table note)",
       "24": "the paper prints the line OI 990.797 (100929 cm^-1, 1.7 x 10^2) twice, as rows 21 and 24; the repeat is dropped"
     },
     "uncertainty": {
       "relative": 0.1,
       "level": "not stated",
       "relative_rows": {
         "2": 0.15,
         "3": 0.15,
         "5": 0.15,
         "7": 0.15,
         "8": 0.15,
         "11": 0.15,
         "12": 0.15,
         "13": 0.15,
         "15": 0.15,
         "18": 0.15
       }
     }
   }

Table I, rows in print order 1\-76\: k \(cm^\-1, natural log, layer reduced to 0 C and 1 atm\) at the source\-line wavelengths, printed as mantissa x 10^2; scale = 1e20 / n0 \(n0 = 2\.6867801e19 cm^\-3\) turns the mantissa into the photoabsorption cross section in Mb \(see the source notes\)\. 10 % for k \> 100 cm^\-1, 15 % for k \<= 100 cm^\-1 \(rows with mantissa \<= 1\.0\)\. Rows with a band location \(printed column\: B\.H\., B\.M\., B\.T\., reference 6 Price and Collins or 8 Tanaka and Takamine\) lie inside molecular bands; the paper doubts their accuracy and meaning\. Values above about 1000 A disagree strongly with the photoelectric data of watanabe\_1953 and metzger\_1964 \(source notes\)\. Row 54 prints 660\.380 A for 660\.280 \(erratum\)\.

weissler\_1952/first\_order
~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "first_order",
     "material": "O2",
     "file": "O2/weissler_1952__first_order.csv",
     "table": "tbl_3deee1da1d4e",
     "quantity": "absorption_cross_section",
     "unit": "Mb",
     "scale": 0.03721927208,
     "abscissa_unit": "angstrom",
     "wavelength_medium": "vacuum",
     "use": "check",
     "uncertainty": {
       "relative": 0.1,
       "level": "not stated"
     }
   }

Table II, 'First order' \(plate LE 25\)\: k \(cm^\-1\) from the first\-order lines, compared with the second\-order ones; scale = 1e18 / n0 to Mb\. A consistency test of the photometry in two grating orders, not fitted\. The OII row prints 644\.188 A for the 644\.148 of Table I \(erratum\)\.

weissler\_1952/second\_order
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "second_order",
     "material": "O2",
     "file": "O2/weissler_1952__second_order.csv",
     "table": "tbl_3deee1da1d4e",
     "quantity": "absorption_cross_section",
     "unit": "Mb",
     "scale": 0.03721927208,
     "abscissa_unit": "angstrom",
     "wavelength_medium": "vacuum",
     "use": "check",
     "uncertainty": {
       "relative": 0.1,
       "level": "not stated"
     }
   }

Table II, 'Second order'\: three of the four values equal Table I's second\-order rows \(750, 720 and 780 cm^\-1 at 644\.825, 645\.167 and 660\.280 A\); the OII line gives 670 here and 690 in Table I\. A duplicate of Table I's measurement\: a check, not fitted\. The OII row prints 644\.188 A for 644\.148 \(erratum\)\.

weissler\_1952/continuum\_f
~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

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

1 inline points in the source record.

p\. 203\: 'When integrating graphically the dotted curve in Fig\. 1 representing continuous absorption, a mean oscillator strength of approximately f=6 was found', agreeing with Ladenburg and Wolfsohn's f3 = 5\.9\. The dotted curve joins 'roughly the lowest measured k\-values between 1000A and 300A' and is 'probably a reasonable approximation to the continuous absorption' below 740 A \(p\. 202\); the range of the integral is not stated\. Index abscissa\: an integrated strength, not a line\. Approximate; a check\.

Formulas
--------

weissler\_1952/ladenburg\_wolfsohn
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "ladenburg_wolfsohn",
     "material": "O2",
     "equation": "text, p. 200 (reproduced)",
     "printed": "represented by a three term equation containing three characteristic wavelengths, lambda_1 = 1898.6A, lambda_2 = 1467.9A, lambda_3 = 544.36A, and three corresponding oscillator strengths, f_1 = 4.04 x 10^-5, f_2 = 0.202, and f_3 = 5.93",
     "variable": "lambda: wavelength in A (the equation itself is not printed)",
     "state": "not stated",
     "density": "unknown",
     "range": "the interferometric dispersion measured between 5900 A and 1920 A (p. 200)",
     "coefficients": {
       "lambda_1": "1898.6",
       "lambda_2": "1467.9",
       "lambda_3": "544.36",
       "f_1": "4.04e-5",
       "f_2": "0.202",
       "f_3": "5.93"
     },
     "reproduced_from": [
       "R. Ladenburg and G. Wolfsohn, Z. Physik 79, 42 (1932)"
     ],
     "check": "Read as a per-molecule oscillator model alpha = sum f_i / (E_i^2 - omega^2) (atomic units, E_i = hc/lambda_i), it gives the static polarizability 10.562 au and 10.774 au at 589 nm, 11.510 au at 300 nm, 13.694 au at 200 nm: 0.24-0.45 % below the stored fit/O2 (10.587, 10.805, 11.550, 13.755 au) (computed 2026-09-25)."
   }

Quoted without the equation; the f\_i are classical oscillator strengths per molecule\. Watanabe et al\. \(1953\) quote lambda\_2 = 1468A from the same work and Koch's \(1912\) lambda\_2 = 1421A\. The original is not in the library \(missing\-K\)\.

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

.. code-block:: text

   [
     {
       "dataset": "table_1",
       "row": "54",
       "column": "x",
       "printed": "660.380",
       "corrected": "660.280",
       "reason": "The second-order NII line is printed 660.380 A in Table I; the same line is 660.280 A in Table II, and Table I's own wave number, 151450 cm^-1, is 1e8/660.280 (660.380 would be 151428).",
       "evidence": "Table I (page 3 continuation, image tbl_3c7b2b7dceeb.jpg) and Table II (tbl_3deee1da1d4e.jpg), checked 2026-09-25; Table I's k (7.8 x 10^2) equals Table II's second-order 780 cm^-1 at 660.280."
     },
     {
       "dataset": "first_order",
       "row": "644.188",
       "column": "x",
       "printed": "644.188",
       "corrected": "644.148",
       "reason": "Table II prints the OII line as 644.188 A; Table I has no such line but OII (second order) 644.148 A with the wave number 155244 cm^-1 = 1e8/644.148 (644.188 would be 155234). The other three Table II lines are Table I lines.",
       "evidence": "Tables I and II, images checked 2026-09-25. Moderately certain: Table II's second-order k (670) differs from Table I's (690) for this line, while it equals Table I's for the other three."
     },
     {
       "dataset": "second_order",
       "row": "644.188",
       "column": "x",
       "printed": "644.188",
       "corrected": "644.148",
       "reason": "As for first_order: the OII line of Table I is 644.148 A (wave number 155244 cm^-1).",
       "evidence": "Tables I and II, images 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.