simmons_1978 ============ A\. C\. Simmons, "The refractive index and Lorentz\-Lorenz functions of propane, nitrogen and carbon\-dioxide in the spectral range 15803\-22002 cm\-1 and at 944 cm\-1", Opt\. Commun\. 25, 211 \(1978\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1016/0030\-4018\(78\)90309\-7 `__ **Source kind:** measurement **Recorded technique:** Mach\-Zehnder interferometry with He\-Ne \(SL10\), tuneable argon\-ion \(CR2\) and tuneable CO2 \(Sylvania 941P\) lasers; brass test cells of 1\.016 m and 0\.493 m with optical flats, evacuated below 0\.01 Torr; pressure by MacLeod gauge, Bourdon test gauge and mercury manometer, gas temperature by two chromel\-alumel thermocouples; fringes counted while the filled cell was slowly evacuated, dn = m lambda/l \(p\. 211\)\. N2 99\.9 %, CO2 99\.8 %\. **Materials in structured entries:** CO2, N2 **Dataset quantities:** molar\_refractivity, refractivity **Contents:** 4 datasets; 0 formulas. Curation notes -------------- Page numbers are the journal's \(211\-214; pdf page 1 = p\. 211\)\. Two reductions of the same measurements \(Table, p\. 213\)\: the Lorentz\-Lorenz function at 300 K, the molar refraction \(n^2 \- 1\)/\(\(n^2 \+ 2\) rho\) = A\_R with the higher virial terms neglected \(Eq\. 2, p\. 213\), in cm^3/mol, with densities from published data \(Kay and Laby; Din's thermodynamic functions\)\: a real\-gas reduction; and the refractive index at 'NTP', printed as n\. NTP is not defined in the paper; with the LL function and the real\-gas density at 0 C and 1 atm, 1\.5 A\_R rho gives N2 299\.9, 297\.9, 287\.9 and CO2 454\.8, 440\.0, 432\.6 \(x 1e\-6\) against the printed 302, 295, 290 and 455, 442, 435, while 15 C or 20 C would be 5\-7 % lower\: NTP is taken as 0 C, 1 atm \(checked 2026\-09\-25\)\. The LL datasets are primary; the NTP refractivities, the same data, are 'check'\. Uncertainties\: the \+\- values of the table, level not stated\. Measurements 'at a temperature of 300 \+\- 1 K' \(abstract\)\. Discrepancy \(p\. 211 against p\. 213\)\: the abstract gives the LL function at 944 cm^\-1 as 4\.32 \+\- 0\.09 \(N2\) and 6\.37 \+\- 0\.09 \(CO2\) cm^3/mol, the table 4\.30 \+\- 0\.10 and 6\.42 \+\- 0\.10 \(propane agrees, 15\.77 \+\- 0\.18\)\. Which is right cannot be decided from the paper; the table's values are extracted \(TC\-176\)\. Wave numbers\: 15803 cm^\-1 is 1/\(632\.8 nm\) and 22002 cm^\-1 1/\(454\.5 nm\), the He\-Ne and Ar\+ lines' air\-wavelength labels inverted \(the He\-Ne line's vacuum wave number, 1/632\.99 nm = 15798 cm^\-1, is quoted from memory\)\: 'air wave numbers', stored as vacuum wave numbers \(the format has no air wave number\); the 3e\-4 relative error of the abscissa changes the LL function by less than 1e\-5 of itself, far below the stated uncertainty\. 944 cm^\-1 is the CO2 laser's 10\.6 um line\. Fig\. 3 \(n \- 1 at NTP against wave number, also for He, Ar, CO and propane\) and Fig\. 4 \(the LL function\) hold further points, including values 'obtained from published data' \(the CRC Handbook\), only as figures\: not extracted\. Propane is not a curated species; the He, Ar and CO measurements appear only in Fig\. 3 \(no CO value is printed in the text or tables; checked\)\. **Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- simmons\_1978/LL\_N2 ~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "LL_N2", "material": "N2", "file": "N2/simmons_1978__LL_N2.csv", "table": "tbl_fe193a93ae5a", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "cm-1", "wavelength_medium": "vacuum", "use": "primary", "uncertainty": { "column": true, "level": "not stated" } } Table, 'LL function at 300 K' at 22002, 15803 and 944 cm^\-1 \(air wave numbers, see the source notes\)\. simmons\_1978/LL\_CO2 ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "LL_CO2", "material": "CO2", "file": "CO2/simmons_1978__LL_CO2.csv", "table": "tbl_fe193a93ae5a", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "cm-1", "wavelength_medium": "vacuum", "use": "primary", "uncertainty": { "column": true, "level": "not stated" } } Table, 'LL function at 300 K' at 22002, 15803 and 944 cm^\-1\. The 944 cm^\-1 value \(10\.6 um\) includes CO2's infrared \(vibrational\) contribution from its bands\. simmons\_1978/ntp\_N2 ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "ntp_N2", "material": "N2", "file": "N2/simmons_1978__ntp_N2.csv", "table": "tbl_fe193a93ae5a", "quantity": "refractivity", "abscissa_unit": "cm-1", "wavelength_medium": "vacuum", "state": "1atm_0C", "density": "unknown", "use": "check", "uncertainty": { "column": true, "level": "not stated" } } Table, 'Refractive index at NTP', stored as n \- 1\: the same measurements as LL\_N2; NTP read as 0 C, 1 atm \(see the source notes\)\. simmons\_1978/ntp\_CO2 ~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "ntp_CO2", "material": "CO2", "file": "CO2/simmons_1978__ntp_CO2.csv", "table": "tbl_fe193a93ae5a", "quantity": "refractivity", "abscissa_unit": "cm-1", "wavelength_medium": "vacuum", "state": "1atm_0C", "density": "unknown", "use": "check", "uncertainty": { "column": true, "level": "not stated" } } Table, 'Refractive index at NTP', stored as n \- 1\: the same measurements as LL\_CO2; NTP read as 0 C, 1 atm\. Formulas -------- No formulas are recorded. 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 ` for the checks and decisions.