griesmann_1999
==============

U\. Griesmann and J\. H\. Burnett, Opt\. Lett\. 24, 1699 \(1999\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/griesmann_1999.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1364/ol\.24\.001699 <https://doi.org/10.1364/ol.24.001699>`__

**Source kind:** measurement

**Recorded technique:** NIST FT700 vacuum\-ultraviolet Fourier\-transform spectrometer \(scanning Mach\-Zehnder, CaF2 optics, resolving power 1\.3e6 at 150 nm\) whose tank is evacuated and then filled with ultra\-high\-purity N2 \(O2 below 10 ppm\) at about 103 kPa\: the refractive index is the ratio of the wave numbers of 31 Fe\-Ne hollow\-cathode lines in gas and vacuum, corrected for the index of N2 at the He\-Ne reference\-laser wave number \(Eq\. 1\)\. Gas temperature by a calibrated silicon diode, within 0\.03 C of the bench\.

**Materials in structured entries:** N2

**Dataset quantities:** refractivity

**Contents:** 1 dataset; 1 formula.

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

Reduced to 273\.15 K and 101 325 Pa with the Lorentz\-Lorenz formula \(Eqs\. 2\-3\) and Peck & Khanna's compressibility Z = 1 \- P \(317\.6 \- T\) 1e\-5 / 101325 \(Eq\. 4\)\: density = real\. Wavelengths are vacuum\. 'The combined standard uncertainty was found to be 0\.2 x 10^\-6' \(p\. 1699\), from the line wave numbers and n\(sigma\_HeNe\)\.

The absolute scale is not independent\: 'the pressure in the spectrometer tank was measured \.\.\. using the known refractive index of nitrogen in the ultraviolet \[Abjean et al\. 1970\] and the accurately known wave numbers of spectral lines of iron \.\.\. using the observed line shifts' \(p\. 1700\), with a capacitance manometer \(0\.15 %\) only as a consistency check\. The refractivities are therefore tied to Abjean et al\.'s UV values \(and n at 633 nm to Peck & Khanna 1966\) at the level of those works' accuracy; the paper states no separate systematic uncertainty for this, so none is set\. What the data add is the shape of the dispersion down to 149 nm\. In a joint fit with Abjean's data \(not in the library\) or with other N2 UV data they are not independent in scale\.

The paper claims 'the largest deviation of any data point from the fitted Sellmeier formula is smaller than the standard uncertainty of 0\.2 x 10^\-6' \(p\. 1700\); Table 1 does not bear this out \(see the formula\)\.

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

Datasets
--------

griesmann\_1999/experiment
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "experiment",
     "material": "N2",
     "file": "N2/griesmann_1999__experiment.csv",
     "table": "tbl_0e295af4655d",
     "quantity": "refractivity",
     "scale": 1e-06,
     "abscissa_unit": "nm",
     "wavelength_medium": "vacuum",
     "state": "1atm_0C",
     "density": "real",
     "use": "primary",
     "uncertainty": {
       "absolute": 0.2,
       "level": "1 sigma"
     }
   }

Scale tied to Abjean et al\. \(1970\) through the optical pressure measurement \(see the source notes\)\.

Formulas
--------

griesmann\_1999/sellmeier
~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "sellmeier",
     "form": "dn_sigma2",
     "terms": {
       "scale": "1e-6",
       "B": [
         "1.9662731e6",
         "2.7450825e4"
       ],
       "C": [
         "22086.66",
         "133.85688"
       ]
     },
     "range_nm": [
       150.0,
       270.0
     ],
     "material": "N2",
     "equation": "Eq. (5), p. 1700",
     "printed": "10^6 x (n - 1)|_(273.15 K, 101,325 Pa) = 1.9662731 x 10^6/(22086.66 - sigma^2) + 2.7450825 x 10^4/(133.85688 - sigma^2)",
     "variable": "sigma: vacuum wavenumber in um^-1",
     "state": "1atm_0C",
     "density": "real",
     "range": "150-270 nm (p. 1700); 'between the onset of nitrogen absorption ... near 145 nm, and 270 nm' (p. 1701)",
     "coefficients": {
       "B1": "1.9662731e6",
       "C1": "22086.66",
       "B2": "2.7450825e4",
       "C2": "133.85688"
     },
     "check": "Against Table 1: rms 0.16, largest deviations -0.52 (149.4169 nm), -0.29 (216.6774, 165.6338 nm), -0.23 (225.9511 nm), not all below 0.2 as the paper says. A free least-squares refit of the same form to Table 1 gives rms 0.145 and max 0.37, so the printed coefficients are close to optimal and not misprinted; the claim is presumably about the unrounded data (Table 1 is rounded to 0.1) or excludes the 149.4 nm point (checked 2026-09-24)."
   }

The first term's pole is at 6\.7 nm \(C1 = 22086\.66 um^\-2\)\: effectively a slowly varying background\.

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.