marchetti_2007
==============

S\. Marchetti and R\. Simili, Infrared Phys\. Technol\. 50, 78 \(2007\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/marchetti_2007.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1016/j\.infrared\.2006\.07\.003 <https://doi.org/10.1016/j.infrared.2006.07.003>`__

**Source kind:** measurement

**Recorded technique:** The differential two\-Fabry\-Perot technique of marchetti\_2006 with a tunable single\-mode RF\-excited CO2 laser \(400 mbar mixture, 700 uJ, 3 us pulses at 1 kHz\) on 27 lines of the 9 and 10 um bands; 209 cm gas cell; residual thermal drift \(0\.35 fringes per degree C\) removed; 'our measurement limit is the accuracy of our pressure measurement \(0\.4%\)' \(p\. 79\)\.

**Materials in structured entries:** CO2

**Dataset quantities:** refractivity

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

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

Values are the pressure coefficient dn with n = 1 \+ dn P \(Eq\. 1\), in 1e\-4 per atm, at 'T = 21°' \(21 degrees C\); the paper converts other data to 21 degrees C 'following the gas perfect relation' \(Eq\. 3\), so each value is taken as the refractivity at 1 atm, 294\.15 K with the ideal\-gas density\. The per\-line errors \(last digits, 0\.3\-0\.7 %\) are of unstated level and presumably include the 0\.4 % pressure accuracy, which is common to all lines \(not separated\)\. Frequencies are vacuum wavenumbers in cm^\-1\.

Consistency\: marchetti\_2006's CO2 value at 10\.57 um \(946 cm^\-1\), 4\.087 at 23 degrees C, scaled to 21 degrees C by T \(296\.15/294\.15\) is 4\.115, against 4\.114 \(12\) here at 1P18 \(946 cm^\-1\)\. The conclusion \(p\. 80\) calls Simmons's 10\.59 um value '5% overestimated'\.

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

Datasets
--------

marchetti\_2007/experiment\_CO2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "experiment_CO2",
     "material": "CO2",
     "file": "CO2/marchetti_2007__experiment_CO2.csv",
     "table": "tbl_33adeac1f5b0",
     "quantity": "refractivity",
     "scale": 0.0001,
     "abscissa_unit": "cm-1",
     "wavelength_medium": "vacuum",
     "state": {
       "pressure_atm": 1,
       "temperature_c": 21
     },
     "density": "ideal",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "not stated"
     }
   }

The table's 27 lines; row ids are the line labels as printed \(1R\.\., 1P\.\. are the 10\-um\-band lines, usually written 10R\.\., 10P\.\.\)\.

Formulas
--------

marchetti\_2007/eq4
~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "eq4",
     "material": "CO2",
     "equation": "Eq. (4), p. 80",
     "printed": "dn(v) = -0.2404 + 7.8801E-3 v - 3.454E-6 v^2",
     "variable": "v: vacuum wavenumber in cm^-1; dn in 1e-4 per atm at 21 degrees C",
     "state": "{ pressure_atm = 1, temperature_c = 21 } (dn times 1 atm)",
     "density": "ideal",
     "range": "931-1083.5 cm^-1 ('valid only in the 10 um region')",
     "coefficients": {
       "a0": "-0.2404",
       "a1": "7.8801e-3",
       "a2": "-3.454e-6"
     },
     "check": "Reproduces the 27 tabulated values with residuals within their stated errors (largest 0.021 at 1P16 against an error of 0.020). Checked 2026-09-24."
   }

A parabola fitted to the table, not a physical dispersion model\.

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.