egan_2019
=========

P\. F\. Egan, J\. A\. Stone, J\. K\. Scherschligt, and A\. H\. Harvey, J\. Vac\. Sci\. Technol\. A 37, 031603 \(2019\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/egan_2019.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1116/1\.5092185 <https://doi.org/10.1116/1.5092185>`__

**Source kind:** measurement

**Recorded technique:** Heterodyne laser refractometry in the MIRE triple\-cell apparatus \(NIST\), He\-Ne laser at 632\.9908\(2\) nm, on the isotherm T\_90 = 293\.15 K \(thermodynamic T = 293\.1529\(13\) K with T \- T\_90 = 2\.9\(4\) mK\)\. Pressure from transducers calibrated in situ against helium refractivity at a known temperature \(the helium relation from ab initio theory\), so the pressure is thermodynamic, not mechanical\. Refractivity measured at 50\-500 kPa in 30 kPa steps; p adjusted to the isotherm with \(dp/dT\)\_rho from REFPROP; Eq\. \(3\) p = c\_1 \(n\-1\) \+ c\_2 \(n\-1\)^2 \+ c\_3 \(n\-1\)^3 fitted by weighted orthogonal distance regression \(ODRPACK\); A\_R = 2RT/\(3 c\_1\) with R = k\_B N\_A \(CODATA 2017 values, exact in the 2019 SI\) \(pp\. 4, 9\-10\)\. Gas grades\: Ne 99\.9995 %, Ar 99\.9999 %, Xe 99\.9995 %, N2 99\.9999 %, CO2 99\.9995 %, N2O 99\.9999 % \(p\. 12\)\.

**Materials in structured entries:** Ar, CO2, N2, N2O, Ne, Xe

**Dataset quantities:** molar\_refractivity

**Contents:** 33 datasets; 6 formulas.

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

Page numbers are the library pdf pages \(pdf page 1 is a publisher's cover\)\. A\_R is the zero\-density molar refractivity \(n^2 \- 1\)/\(\(n^2 \+ 2\) rho\) at 632\.9908 nm, 'A\_R = \(4 pi/3\) N\_A \(alpha \+ chi\)', i\.e\. it includes the magnetic susceptibility \(p\. 3\)\. Wavelength\: vacuum \(632\.9908 nm is the He\-Ne vacuum wavelength; the paper does not say 'vacuum' but gives the value to 0\.2 pm\)\. Temperature 293\.1529 K\: only nitrogen's A\_R is expected to depend on it \(p\. 13\)\.

Uncertainty\: Table II, relative standard uncertainty of A\_R \(x 10^\-6\)\: combined Ne 16\.0, Ar 15\.1, Xe 15\.5, N2 15\.1, CO2 15\.1, N2O 15\.3, dominated by the pressure calibration \(14\.2\-14\.5\); T 4\.5, n \- 1 \(5\.2 Ne \.\.\. 0\.5 Xe\), impurity \(3\.0 Xe, 2\.5 Ne\), regression \(1\.2\-2\.2\)\. Table III's parenthesised values are these standard uncertainties; Table I's bracketed c\_1, c\_2, c\_3 uncertainties are statistical only\. A\_R from Eq\. \(3\) and from the exact Lorentz\-Lorenz form agree to 8e\-7 \(p\. 10\); the zero\-density intercept of the EOS analysis \(Fig\. 4\) agrees within 1e\-6 \(2e\-6 for Ne\)\.

Checks \(2026\-09\-25\)\: 2RT/\(3 c\_1\) with Table I's c\_1 and T = 293\.1529 K reproduces Table III's A\_R to 4e\-7 for all six gases; Egan et al\.'s 2016 nitrogen c\_1^303K = 3\.7764715e8 Pa at 302\.919 K \(p\. 13\) gives 4\.446141, Table III's 4\.446139\(16\)\.

Table III's literature values are extracted as reproduced datasets \(stored at '633 nm', the caption's wording; the literature temperatures are not given, which matters for N2 only\)\. Egan and Stone's 2011 values are printed adjusted by \+19\.3e\-6 A\_R \(note a; check, see egan\_2011\)\. Egan et al\. treat all tabulated uncertainties as standard uncertainties \(Birch's converted from 99 % with k = 2\.58\); whether Achtermann et al\.'s were one sigma is not discussed \(achtermann\_1991 states three standard deviations for its virial coefficients\)\.

Text values\: A\_eps \-\> R of Ne 1\.00028\(6\) and Ar 4\.1956\(6\) cm^3/mol at 633 nm, derived by the authors from Gaiser and Fellmuth's \(2018\) static A\_eps with Kumar and Thakkar's \(2010\) Cauchy moments and Barter et al\.'s magnetic susceptibilities \(p\. 12; inline dataset, check\)\. Egan et al\. 2016 \(N2, 302\.919 K, p \< 180 kPa\)\: c\_1 = 3\.7764715e8 Pa \(printed with an unmapped dot glyph over the last digits in the library text\), c\_2 = \-2\.982e8 Pa, c\_3 = 1\.24e10 Pa \(p\. 13; not extracted\)\. Temperature dependence of N2's A\_R \(p\. 13, not extracted\: no quantity\)\: Hohm and Kerl 78\(47\)e\-7, Schmidt and Moldover 62\(11\)e\-7 \(static\), Harvey and Lemmon 82e\-7, Buldakov et al\. 48\(1\)e\-7 \(optical, theory\), Sharipov et al\. 51e\-7 \(static, theory\), a fit to Fig\. 5's literature 137e\-7, this work with Egan 2016 33e\-7 \(cm^3/mol\)/K\.

Not extracted\: the n \- 1, p, T data \(supplementary material, not in the library\); Table II \(budget, summarised above\)\.

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

Datasets
--------

egan\_2019/A\_R\_Ne
~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "A_R_Ne",
     "material": "Ne",
     "file": "Ne/egan_2019__A_R_Ne.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     },
     "parameters": {
       "temperature_k": 293.1529
     }
   }

Table III 'This work'\: A\_R = 1\.000211\(16\) cm^3/mol at 632\.9908 nm, 293\.1529 K \(= 2RT/\(3 c\_1\), Table I\)\. 38 ppm below Rourke's \(2021\) theory\-plus\-DCGT estimate 1\.000249\(14\) \(rourke\_2021\)\.

egan\_2019/A\_R\_Ar
~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "A_R_Ar",
     "material": "Ar",
     "file": "Ar/egan_2019__A_R_Ar.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     },
     "parameters": {
       "temperature_k": 293.1529
     }
   }

Table III 'This work'\: A\_R = 4\.195685\(64\) cm^3/mol at 632\.9908 nm, 293\.1529 K\.

egan\_2019/A\_R\_Xe
~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "A_R_Xe",
     "material": "Xe",
     "file": "Xe/egan_2019__A_R_Xe.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     },
     "parameters": {
       "temperature_k": 293.1529
     }
   }

Table III 'This work'\: A\_R = 10\.39081\(16\) cm^3/mol at 632\.9908 nm, 293\.1529 K\.

egan\_2019/A\_R\_N2
~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "A_R_N2",
     "material": "N2",
     "file": "N2/egan_2019__A_R_N2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     },
     "parameters": {
       "temperature_k": 293.1529
     }
   }

Table III 'This work'\: A\_R = 4\.446107\(68\) cm^3/mol at 632\.9908 nm and 293\.1529 K \(nitrogen's A\_R depends on temperature, p\. 13\)\.

egan\_2019/A\_R\_CO2
~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "A_R_CO2",
     "material": "CO2",
     "file": "CO2/egan_2019__A_R_CO2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     },
     "parameters": {
       "temperature_k": 293.1529
     }
   }

Table III 'This work'\: A\_R = 6\.64343\(11\) cm^3/mol at 632\.9908 nm, 293\.1529 K\.

egan\_2019/A\_R\_N2O
~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "A_R_N2O",
     "material": "N2O",
     "file": "N2O/egan_2019__A_R_N2O.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     },
     "parameters": {
       "temperature_k": 293.1529
     }
   }

Table III 'This work'\: A\_R = 7\.49921\(12\) cm^3/mol at 632\.9908 nm, 293\.1529 K\.

egan\_2019/A\_eps\_to\_R\_Ne
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "A_eps_to_R_Ne",
     "material": "Ne",
     "table": "text",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "check",
     "reproduced_from": [
       "gaiser_2018",
       "kumar_2010",
       "C. Barter, R. G. Meisenheimer, and D. P. Stevenson, J. Phys. Chem. 64, 1312 (1960)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

1 inline points in the source record.

p\. 12\: A\_eps\-\>R\(Ne\) = 1\.00028\(6\) cm^3/mol, Gaiser and Fellmuth's static A\_eps corrected to 633 nm with Kumar and Thakkar's Cauchy moments plus Barter et al\.'s chi; 'uncertainty \.\.\. dominated by that of the dispersion correction'\. Derived by the authors\: a check \(agrees with this work's 1\.000211\(16\) within mutual uncertainties\)\.

egan\_2019/A\_eps\_to\_R\_Ar
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "A_eps_to_R_Ar",
     "material": "Ar",
     "table": "text",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "check",
     "reproduced_from": [
       "gaiser_2018",
       "kumar_2010",
       "C. Barter, R. G. Meisenheimer, and D. P. Stevenson, J. Phys. Chem. 64, 1312 (1960)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

1 inline points in the source record.

p\. 12\: A\_eps\-\>R\(Ar\) = 4\.1956\(6\) cm^3/mol, as for neon; 'in excellent agreement with our result for argon'\. A check\.

egan\_2019/achtermann\_1993\_Ne
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "achtermann_1993_Ne",
     "material": "Ne",
     "file": "Ne/egan_2019__achtermann_1993_Ne.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "H. J. Achtermann, J. G. Hong, G. Magnus, R. A. Aziz, and M. J. Slaman, J. Chem. Phys. 98, 2308 (1993)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 1\.0012\(0\.0002\) cm^3/mol, Achtermann et al\. \(Ref\. 26\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/birch\_1991\_Ne
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "birch_1991_Ne",
     "material": "Ne",
     "file": "Ne/egan_2019__birch_1991_Ne.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "birch_1991"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 1\.00170\(0\.00008\) cm^3/mol, Birch \(Ref\. 47\); 'measured at 633 nm' \(caption; stored at 633 nm\)\. Birch stated '\<= 2\.0 parts per 10^4' at 99 % confidence; Egan et al\. divide by 2\.58 to give the standard uncertainty \(p\. 12\)\.

egan\_2019/burns\_1986\_Ne
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "burns_1986_Ne",
     "material": "Ne",
     "file": "Ne/egan_2019__burns_1986_Ne.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "burns_1986"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 0\.999\(0\.001\) cm^3/mol, Burns et al\. \(Ref\. 45\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/hohm\_kerl\_1990\_Ne
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "hohm_kerl_1990_Ne",
     "material": "Ne",
     "file": "Ne/egan_2019__hohm_kerl_1990_Ne.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "U. Hohm and K. Kerl, Mol. Phys. 69, 803 (1990)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 1\.001\(0\.001\) cm^3/mol, Hohm and Kerl \(Ref\. 46\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/achtermann\_1993\_Ar
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "achtermann_1993_Ar",
     "material": "Ar",
     "file": "Ar/egan_2019__achtermann_1993_Ar.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "H. J. Achtermann, J. G. Hong, G. Magnus, R. A. Aziz, and M. J. Slaman, J. Chem. Phys. 98, 2308 (1993)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.1955\(0\.0003\) cm^3/mol, Achtermann et al\. \(Ref\. 26\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/birch\_1991\_Ar
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "birch_1991_Ar",
     "material": "Ar",
     "file": "Ar/egan_2019__birch_1991_Ar.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "birch_1991"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.1953\(0\.0003\) cm^3/mol, Birch \(Ref\. 47\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/coulon\_1981\_Ar
~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "coulon_1981_Ar",
     "material": "Ar",
     "file": "Ar/egan_2019__coulon_1981_Ar.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "R. Coulon, G. Montixi, and R. Occelli, Can. J. Phys. 59, 1555 (1981)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.1973\(0\.0005\) cm^3/mol, Coulon et al\. \(Ref\. 48\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/egan\_2011\_adjusted\_Ar
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "egan_2011_adjusted_Ar",
     "material": "Ar",
     "file": "Ar/egan_2019__egan_2011_adjusted_Ar.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "check",
     "reproduced_from": [
       "egan_2011"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.19553\(0\.00006\) cm^3/mol, Egan and Stone \(Ref\. 50\), note a\: 'Adjusted by \+19\.3 x 10^\-6 A\_R from what was reported in Ref\. 50 to account for two biases' \(T \- T90 = 2\.9 mK, 9\.9 ppm; a blundered helium\-permeation extrapolation, 9\.4 ppm; p\. 12\)\. The authors 'consider the present measurements to supersede those of 2011'\: a check, not the original; 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/hohm\_1994\_Ar
~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "hohm_1994_Ar",
     "material": "Ar",
     "file": "Ar/egan_2019__hohm_1994_Ar.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "U. Hohm, Mol. Phys. 81, 157 (1994)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.1962\(0\.0007\) cm^3/mol, Hohm \(Ref\. 27\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/hou\_1994\_Ar
~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "hou_1994_Ar",
     "material": "Ar",
     "file": "Ar/egan_2019__hou_1994_Ar.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "W. Hou and R. Thalmann, Measurement 13, 307 (1994)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.1955\(0\.0006\) cm^3/mol, Hou and Thalmann \(Ref\. 49\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/achtermann\_1993\_Xe
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "achtermann_1993_Xe",
     "material": "Xe",
     "file": "Xe/egan_2019__achtermann_1993_Xe.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "H. J. Achtermann, J. G. Hong, G. Magnus, R. A. Aziz, and M. J. Slaman, J. Chem. Phys. 98, 2308 (1993)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 10\.345\(0\.002\) cm^3/mol, Achtermann et al\. \(Ref\. 26\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/burns\_1986\_Xe
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "burns_1986_Xe",
     "material": "Xe",
     "file": "Xe/egan_2019__burns_1986_Xe.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "burns_1986"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 10\.36\(0\.01\) cm^3/mol, Burns et al\. \(Ref\. 45\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/hohm\_trumper\_1996\_Xe
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "hohm_trumper_1996_Xe",
     "material": "Xe",
     "file": "Xe/egan_2019__hohm_trumper_1996_Xe.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "U. Hohm and U. Trümper, Mol. Phys. 89, 943 (1996)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 10\.395\(0\.006\) cm^3/mol, Hohm and Trümper \(Ref\. 51\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/achtermann\_1986\_N2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "achtermann_1986_N2",
     "material": "N2",
     "file": "N2/egan_2019__achtermann_1986_N2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "H. J. Achtermann, T. K. Bose, H. Rögener, and J. M. St-Arnaud, Int. J. Thermophys. 7, 709 (1986)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.446\(0\.001\) cm^3/mol, Achtermann et al\. \(Ref\. 53\); 'measured at 633 nm' \(caption; stored at 633 nm\)\. Temperature not given in the table \(nitrogen's A\_R depends on T; Fig\. 5, figure only\)\.

egan\_2019/achtermann\_1991\_N2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "achtermann_1991_N2",
     "material": "N2",
     "file": "N2/egan_2019__achtermann_1991_N2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "achtermann_1991"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.4464\(0\.0005\) cm^3/mol, Achtermann et al\. \(Ref\. 25\); 'measured at 633 nm' \(caption; stored at 633 nm\)\. Temperature not given in the table \(nitrogen's A\_R depends on T; Fig\. 5, figure only\)\.

egan\_2019/birch\_1991\_N2
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "birch_1991_N2",
     "material": "N2",
     "file": "N2/egan_2019__birch_1991_N2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "birch_1991"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.4457\(0\.0003\) cm^3/mol, Birch \(Ref\. 47\); 'measured at 633 nm' \(caption; stored at 633 nm\)\. Temperature not given in the table \(nitrogen's A\_R depends on T; Fig\. 5, figure only\)\.

egan\_2019/egan\_2011\_adjusted\_N2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "egan_2011_adjusted_N2",
     "material": "N2",
     "file": "N2/egan_2019__egan_2011_adjusted_N2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "check",
     "reproduced_from": [
       "egan_2011"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.44594\(0\.00006\) cm^3/mol, Egan and Stone \(Ref\. 50\), note a\: 'Adjusted by \+19\.3 x 10^\-6 A\_R from what was reported in Ref\. 50 to account for two biases' \(T \- T90 = 2\.9 mK, 9\.9 ppm; a blundered helium\-permeation extrapolation, 9\.4 ppm; p\. 12\)\. The authors 'consider the present measurements to supersede those of 2011'\: a check, not the original; 'measured at 633 nm' \(caption; stored at 633 nm\)\. Temperature not given in the table \(nitrogen's A\_R depends on T; Fig\. 5, figure only\)\.

egan\_2019/egan\_2016\_N2
~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "egan_2016_N2",
     "material": "N2",
     "file": "N2/egan_2019__egan_2016_N2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "P. F. Egan, J. A. Stone, J. E. Ricker, and J. H. Hendricks, Rev. Sci. Instrum. 87, 053113 (2016)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     },
     "parameters": {
       "temperature_k": 302.919
     }
   }

Table III\: A\_R = 4\.446139\(0\.000016\) cm^3/mol, Egan et al\. \(Ref\. 12\), Fabry\-Perot refractometer at 302\.919 K with a mercury manometer \(p\. 13\); about 4 times more accurate than this work for N2; 'measured at 633 nm' \(caption; stored at 633 nm\)\. Temperature 302\.919 K \(p\. 13\)\.

egan\_2019/hou\_1994\_N2
~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "hou_1994_N2",
     "material": "N2",
     "file": "N2/egan_2019__hou_1994_N2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "W. Hou and R. Thalmann, Measurement 13, 307 (1994)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.4455\(0\.0006\) cm^3/mol, Hou and Thalmann \(Ref\. 49\); 'measured at 633 nm' \(caption; stored at 633 nm\)\. Temperature not given in the table \(nitrogen's A\_R depends on T; Fig\. 5, figure only\)\.

egan\_2019/montixi\_1983\_N2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "montixi_1983_N2",
     "material": "N2",
     "file": "N2/egan_2019__montixi_1983_N2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "G. Montixi, R. Coulon, and R. Occelli, Can. J. Phys. 61, 473 (1983)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 4\.4454\(0\.0005\) cm^3/mol, Montixi et al\. \(Ref\. 52\); 'measured at 633 nm' \(caption; stored at 633 nm\)\. Temperature not given in the table \(nitrogen's A\_R depends on T; Fig\. 5, figure only\)\.

egan\_2019/achtermann\_1991\_CO2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "achtermann_1991_CO2",
     "material": "CO2",
     "file": "CO2/egan_2019__achtermann_1991_CO2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "achtermann_1991"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 6\.644\(0\.001\) cm^3/mol, Achtermann et al\. \(Ref\. 25\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/birch\_1991\_CO2
~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "birch_1991_CO2",
     "material": "CO2",
     "file": "CO2/egan_2019__birch_1991_CO2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "birch_1991"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 6\.6418\(0\.0005\) cm^3/mol, Birch \(Ref\. 47\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/hohm\_1994\_CO2
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "hohm_1994_CO2",
     "material": "CO2",
     "file": "CO2/egan_2019__hohm_1994_CO2.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "U. Hohm, Mol. Phys. 81, 157 (1994)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 6\.646\(0\.003\) cm^3/mol, Hohm \(Ref\. 27\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/birch\_1991\_N2O
~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "birch_1991_N2O",
     "material": "N2O",
     "file": "N2O/egan_2019__birch_1991_N2O.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "birch_1991"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 7\.5021\(0\.0007\) cm^3/mol, Birch \(Ref\. 47\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

egan\_2019/hohm\_1994\_N2O
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "hohm_1994_N2O",
     "material": "N2O",
     "file": "N2O/egan_2019__hohm_1994_N2O.csv",
     "table": "tbl_6d3145de2fcf",
     "quantity": "molar_refractivity",
     "unit": "cm3/mol",
     "abscissa_unit": "nm",
     "use": "reproduced",
     "reproduced_from": [
       "U. Hohm, Mol. Phys. 81, 157 (1994)"
     ],
     "uncertainty": {
       "column": true,
       "level": "1 sigma"
     }
   }

Table III\: A\_R = 7\.5114\(0\.0006\) cm^3/mol, Hohm \(Ref\. 27\); 'measured at 633 nm' \(caption; stored at 633 nm\)\.

Formulas
--------

egan\_2019/pressure\_Ne
~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "pressure_Ne",
     "material": "Ne",
     "equation": "Eq. (3), p. 4, with Table I",
     "printed": "p = c_1 (n - 1) + c_2 (n - 1)^2 + c_3 (n - 1)^3; c_1 x 10^-8 = 16.245968(29) Pa, c_2 x 10^-8 = 119.84(36) Pa, c_3 x 10^-10 = 32.5(98) Pa",
     "variable": "n - 1: refractivity at 632.9908 nm; p: thermodynamic pressure in Pa",
     "state": "T = 293.1529 K, p <= 500 kPa",
     "density": "real",
     "range": "632.9908 nm only; 50-500 kPa at 293.1529 K",
     "coefficients": {
       "c1": "16.245968e8",
       "c2": "119.84e8",
       "c3": "32.5e10"
     },
     "check": "A_R = 2RT/(3 c_1) = 1.0002108 cm^3/mol, Table III's 1.000211 (checked 2026-09-25)."
   }

Not a dispersion formula\: the pressure\-refractivity relation at one wavelength and temperature, c\_2 and c\_3 lump parameters combining B\_rho, B\_R, C\_rho, C\_R \(Eq\. \(4\)\)\. Bracketed uncertainties are statistical only \(Table I caption\)\.

egan\_2019/pressure\_Ar
~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "pressure_Ar",
     "material": "Ar",
     "equation": "Eq. (3), p. 4, with Table I",
     "printed": "p = c_1 (n - 1) + c_2 (n - 1)^2 + c_3 (n - 1)^3; c_1 x 10^-8 = 3.8728820(80) Pa, c_2 x 10^-8 = -11.371(25) Pa, c_3 x 10^-10 = 2.66(17) Pa",
     "variable": "n - 1: refractivity at 632.9908 nm; p: thermodynamic pressure in Pa",
     "state": "T = 293.1529 K, p <= 500 kPa",
     "density": "real",
     "range": "632.9908 nm only; 50-500 kPa at 293.1529 K",
     "coefficients": {
       "c1": "3.8728820e8",
       "c2": "-11.371e8",
       "c3": "2.66e10"
     },
     "check": "A_R = 2RT/(3 c_1) = 4.1956848 cm^3/mol, Table III's 4.195685 (checked 2026-09-25)."
   }

As pressure\_Ne\.

egan\_2019/pressure\_Xe
~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "pressure_Xe",
     "material": "Xe",
     "equation": "Eq. (3), p. 4, with Table I",
     "printed": "p = c_1 (n - 1) + c_2 (n - 1)^2 + c_3 (n - 1)^3; c_1 x 10^-8 = 1.5638229(21) Pa, c_2 x 10^-8 = -14.0785(26) Pa, c_3 x 10^-10 = 0.4956(67) Pa",
     "variable": "n - 1: refractivity at 632.9908 nm; p: thermodynamic pressure in Pa",
     "state": "T = 293.1529 K, p <= 500 kPa",
     "density": "real",
     "range": "632.9908 nm only; 50-500 kPa at 293.1529 K",
     "coefficients": {
       "c1": "1.5638229e8",
       "c2": "-14.0785e8",
       "c3": "0.4956e10"
     },
     "check": "A_R = 2RT/(3 c_1) = 10.390814 cm^3/mol, Table III's 10.39081 (checked 2026-09-25)."
   }

As pressure\_Ne\.

egan\_2019/pressure\_N2
~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "pressure_N2",
     "material": "N2",
     "equation": "Eq. (3), p. 4, with Table I",
     "printed": "p = c_1 (n - 1) + c_2 (n - 1)^2 + c_3 (n - 1)^3; c_1 x 10^-8 = 3.6547460(79) Pa, c_2 x 10^-8 = -4.005(23) Pa, c_3 x 10^-10 = 1.47(15) Pa",
     "variable": "n - 1: refractivity at 632.9908 nm; p: thermodynamic pressure in Pa",
     "state": "T = 293.1529 K, p <= 500 kPa",
     "density": "real",
     "range": "632.9908 nm only; 50-500 kPa at 293.1529 K",
     "coefficients": {
       "c1": "3.6547460e8",
       "c2": "-4.005e8",
       "c3": "1.47e10"
     },
     "check": "A_R = 2RT/(3 c_1) = 4.4461071 cm^3/mol, Table III's 4.446107 (checked 2026-09-25)."
   }

As pressure\_Ne\. Egan et al\. 2016 give c\_1 = 3\.7764715e8, c\_2 = \-2\.982e8, c\_3 = 1\.24e10 Pa at 302\.919 K, p \< 180 kPa \(p\. 13, text only\)\.

egan\_2019/pressure\_CO2
~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "pressure_CO2",
     "material": "CO2",
     "equation": "Eq. (3), p. 4, with Table I",
     "printed": "p = c_1 (n - 1) + c_2 (n - 1)^2 + c_3 (n - 1)^3; c_1 x 10^-8 = 2.4459350(40) Pa, c_2 x 10^-8 = -31.8197(76) Pa, c_3 x 10^-10 = -1.372(31) Pa",
     "variable": "n - 1: refractivity at 632.9908 nm; p: thermodynamic pressure in Pa",
     "state": "T = 293.1529 K, p <= 500 kPa",
     "density": "real",
     "range": "632.9908 nm only; 50-500 kPa at 293.1529 K",
     "coefficients": {
       "c1": "2.4459350e8",
       "c2": "-31.8197e8",
       "c3": "-1.372e10"
     },
     "check": "A_R = 2RT/(3 c_1) = 6.6434276 cm^3/mol, Table III's 6.64343 (checked 2026-09-25)."
   }

As pressure\_Ne\.

egan\_2019/pressure\_N2O
~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "pressure_N2O",
     "material": "N2O",
     "equation": "Eq. (3), p. 4, with Table I",
     "printed": "p = c_1 (n - 1) + c_2 (n - 1)^2 + c_3 (n - 1)^3; c_1 x 10^-8 = 2.1668132(27) Pa, c_2 x 10^-8 = -26.7190(45) Pa, c_3 x 10^-10 = 0.920(16) Pa",
     "variable": "n - 1: refractivity at 632.9908 nm; p: thermodynamic pressure in Pa",
     "state": "T = 293.1529 K, p <= 500 kPa",
     "density": "real",
     "range": "632.9908 nm only; 50-500 kPa at 293.1529 K",
     "coefficients": {
       "c1": "2.1668132e8",
       "c2": "-26.7190e8",
       "c3": "0.920e10"
     },
     "check": "A_R = 2RT/(3 c_1) = 7.4992123 cm^3/mol, Table III's 7.49921 (checked 2026-09-25)."
   }

As pressure\_Ne\.

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 :doc:`review register </register>` for the checks and decisions.