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 · Catalogue · 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

{
  "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

{
  "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

{
  "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

{
  "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 review register for the checks and decisions.