yang_2025 ========= Y\. Yang, J\. A\. Stone and P\. F\. Egan, "Demonstration of dispersion gas barometry", Phys\. Rev\. Appl\. 23, 064041 \(2025\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1103/z9zz\-lqzh `__ **Source kind:** measurement **Recorded technique:** Two\-colour Fabry\-Perot refractometry \(NIST; the apparatus of Egan and Yang 2023\)\: a 15 cm titania\-silicate cavity near 303 K, mirrors dual\-coated for 633 and 1542 nm, interrogated synchronously by a He\-Ne laser at 473\.61187 THz and an ECDL at 194\.36862 THz against comb\-locked references; 100 quadruplets \(two refractivities, pressure from a piston gauge, temperature from a capsule SPRT\) per isotherm, 0\.05\-0\.5 MPa\. For helium, the cavity distortion and a pressure\-calibration parameter are solved from the two refractivities with ab initio helium dispersion \(the 'optical\-pressure scale', epsilon\_p = \(2\.2 \+\- 5\.7\) x 10^\-6\); for Ne, Ar, N2, A\_eps and A\_2 of Eq\. \(4\) are solved at each quadruplet with that distortion \(pp\. 2\-5\)\. **Materials in structured entries:** Ar, He, N2, Ne **Dataset quantities:** molar\_refractivity **Contents:** 11 datasets; 4 formulas. Curation notes -------------- Identity VALIDATED; first page checked \(pdf page 1\: Phys\. Rev\. Applied 23, 064041 \(2025\), published 17 June 2025\)\. Page numbers are the article pages 1\-7 \(= pdf pages\)\. Uncertainties are standard uncertainties \(Table I caption\)\. THE MODEL \(Eq\. 4, p\. 2\)\: A\_R\(nu\) = A\_eps \+ A\_2 nu\_bar^2 \+ A\_4 nu\_bar^4 \+ A\_6 nu\_bar^6 \+ A\_mu with nu\_bar = nu/\(10^14 Hz\), A\_eps = \(4 pi/3\) N\_A alpha\(0\), A\_mu = \(4 pi/3\) N\_A chi\. The two laser frequencies are 473\.61187 and 194\.36862 THz \(vacuum wavelengths 632\.9919 and 1542\.3912 nm, computed\)\. A\_4, A\_6 and A\_mu are assumed \(theory for Ne, Ar; Kumar and Meath's DOSD sums for N2\); only A\_eps and A\_2 are solved, so the measurement's information is the pair \(A\_eps, A\_2\) of Table I\. The raw data are in the NIST repository \(doi 10\.18434/mds2\-3695\), not in the library\. DATASETS\: the A\_eps column of Table I \(static, 'inf'\)\: this work \(primary, Ne, Ar, N2\), and the literature rows \(reproduced\)\. A\_2 has no quantity\: recorded as the formulas ne\_cauchy, ar\_cauchy, n2\_cauchy, he\_A2 \(this work\) with the literature A\_2 in their notes\. In atomic units A\_2 = \(4 pi/3\) N\_A a0^3 S\(\-4\) \(2 pi 10^14 Hz / E\_h/hbar\)^2, i\.e\. S\(\-4\) = A\_2 / \(0\.3738031 cm^3/mol x 2\.30988e\-4\) \(computed with the package's constants\)\: Ne 2\.84906 \(lesiuk\_2020 alpha\_2 2\.850\(7\)\), Ar 27\.9486 \(lesiuk\_2023 27\.976\(15\), 1\.0e\-3 above\), N2 30\.1086 \(nie\_2025's Olney 30\.11\(9\); Kumar and Meath's 25\.70 gives 29\.765\), He 1\.543206 \(theory's A\_2 gives 1\.543203\)\. ACCURACY \(p\. 6\)\: A\_eps 'chiefly dominated by the measured \(optical\) pressure', 5\.7e\-6 from helium dispersion theory, temperature 2\.5e\-6, neon impurity 4\.0e\-6 and kappa 3\.3e\-6; plus an A\_mu discrepancy 'corresponding to about 2 x 10^\-6 A\_eps'\. A\_2\: about 3\.5e\-5 A\_2 for Ne and Ar \(statistics and A\_4, A\_6\), 2\.0e\-4 A\_2 for N2 \(A\_4, A\_6 from the DOSD\)\. 'The A\_2 values deduced from this work are 66 and 16 times more accurate than ab initio theory of neon and argon'\. For helium, A\_eps is fixed to theory and the measured A\_2 = 1\.332468\(6\) x 10^\-4 validates the retardation\-corrected theory \(1\.332465\(5\)\)\. All values refer to about 303 K \(the isotherms 'near 303 K'\); the exact temperatures are in the supplemental material, not in the library\. **Recorded bibliographic identity status:** VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- yang\_2025/A\_eps\_Ne ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "A_eps_Ne", "material": "Ne", "file": "Ne/yang_2025__A_eps_Ne.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "primary", "uncertainty": { "column": true, "level": "1 sigma" }, "parameters": { "temperature_k": 303.0 } } Table I 'This work'\: A\_eps = 0\.994709\(8\) cm^3/mol, the static term of the two\-frequency Cauchy fit \(473\.61187 and 194\.36862 THz\), with A\_4, A\_6 from Lesiuk et al\.'s theory and A\_mu ab initio assumed; on the optical\-pressure scale \(helium dispersion theory\)\. 2\.4 ppm below gaiser\_2018 \(0\.3 sigma\)\. The authors\: 'capacitance measurements that directly access A\_eps will be more reliable than the derived values of this work' \(p\. 6\)\. About 303 K\. yang\_2025/A\_eps\_Ar ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "A_eps_Ar", "material": "Ar", "file": "Ar/yang_2025__A_eps_Ar.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "primary", "uncertainty": { "column": true, "level": "1 sigma" }, "parameters": { "temperature_k": 303.0 } } Table I 'This work'\: A\_eps = 4\.14070\(3\) cm^3/mol, as A\_eps\_Ne \(A\_4, A\_6 from Lesiuk and Jeziorski 2023\)\. 3\.4 ppm above gaiser\_2018\. About 303 K\. yang\_2025/A\_eps\_N2 ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "A_eps_N2", "material": "N2", "file": "N2/yang_2025__A_eps_N2.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "primary", "uncertainty": { "column": true, "level": "1 sigma" }, "parameters": { "temperature_k": 303.0 } } Table I 'This work'\: A\_eps = 4\.38692\(3\) cm^3/mol, as A\_eps\_Ne, with A\_4 and A\_6 from Kumar and Meath's DOSD sums \[22\] and B\_R^\(2\) set to zero; A\_mu for N2 'being finalized' \[28\] \(p\. 6\)\. 30 ppm below nie\_2025's 4\.38705\(16\) \(0\.8 sigma\) and 178 ppm below Schmidt and Moldover's capacitance value 4\.3877\(2\) \(3\.9 sigma\)\. About 303 K\. yang\_2025/lesiuk\_2020\_Ne ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "lesiuk_2020_Ne", "material": "Ne", "file": "Ne/yang_2025__lesiuk_2020_Ne.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "reproduced", "reproduced_from": [ "lesiuk_2020" ], "uncertainty": { "column": true, "level": "1 sigma" } } Table I 'Theoretical \[20\]'\: 0\.9946\(1\) cm^3/mol, lesiuk\_2020's alpha\_0 = 2\.66080 au \(0\.994615 cm^3/mol\) rounded; A\_2 2\.461\(5\) x 10^\-4\. yang\_2025/gaiser\_2018\_Ne ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "gaiser_2018_Ne", "material": "Ne", "file": "Ne/yang_2025__gaiser_2018_Ne.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "reproduced", "reproduced_from": [ "gaiser_2018" ], "uncertainty": { "column": true, "level": "1 sigma" } } Table I 'Experimental \[17\]'\: 0\.994711\(2\), gaiser\_2018's 0\.9947114\(24\) rounded\. yang\_2025/lesiuk\_2023\_Ar ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "lesiuk_2023_Ar", "material": "Ar", "file": "Ar/yang_2025__lesiuk_2023_Ar.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "reproduced", "reproduced_from": [ "lesiuk_2023" ], "uncertainty": { "column": true, "level": "1 sigma" } } Table I 'Theoretical \[21\]'\: 4\.1408\(7\) cm^3/mol, lesiuk\_2023's S\(\-2\) = 11\.0775\(19\) au \(4\.14081\) rounded; A\_2 24\.16\(1\) x 10^\-4 \(lesiuk\_2023's S\(\-4\) 27\.976 gives 24\.155\)\. yang\_2025/gaiser\_2018\_Ar ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "gaiser_2018_Ar", "material": "Ar", "file": "Ar/yang_2025__gaiser_2018_Ar.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "reproduced", "reproduced_from": [ "gaiser_2018" ], "uncertainty": { "column": true, "level": "1 sigma" } } Table I 'Experimental \[17\]'\: 4\.14069\(1\), gaiser\_2018's argon value rounded \(nie\_2025 uses 4\.140686\(10\)\)\. yang\_2025/kumar\_meath\_1992\_N2 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "kumar_meath_1992_N2", "material": "N2", "file": "N2/yang_2025__kumar_meath_1992_N2.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "reproduced", "reproduced_from": [ "A. Kumar and W. J. Meath, Theor. Chim. Acta 82, 131 (1992) (Ref. 22)" ] } Table I 'Experimental \[22\]'\: 4\.388 cm^3/mol \(A\_2 25\.70 x 10^\-4\), printed without uncertainty; Ref\. 22 is Kumar and Meath's constrained DOSD for H2 and N2 \(the library text truncates the reference after 'Theor\. Chim\. Ac'; presumably Theor\. Chim\. Acta 82, 131 \(1992\), as christiansen\_1998 cites Kumar and Meath's N2 DOSD\), labelled 'Experimental' \(a DOSD constrained by experiment\)\. Not in the library\. yang\_2025/schmidt\_moldover\_2003\_N2 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "schmidt_moldover_2003_N2", "material": "N2", "file": "N2/yang_2025__schmidt_moldover_2003_N2.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "reproduced", "reproduced_from": [ "schmidt_2003" ], "uncertainty": { "column": true, "level": "1 sigma" } } Table I 'Experimental \[23\]'\: 4\.3877\(2\) cm^3/mol, Schmidt and Moldover's cross\-capacitor dielectric value \(level as this paper's table, 'standard uncertainty'\)\. The original \(schmidt\_2003, Table V\) prints no 4\.3877\: its two N2 fits give 4\.38782 \(18\) \(two parameters; the text's '4\.3878 \+\- 0\.0009'\) and 4\.38748 \(15\) at 273\.16 K \(with A\_tau\), whose mean 4\.38765 rounds to 4\.3877, as does hohm\_2013's 11\.7379 au \(the same mean\)\. So this is the mean of the two fits, not a printed value; the original states no level for its parenthesised fit uncertainties, and its full budget is about 2\.7e\-4 cm^3/mol \(schmidt\_2003 notes\)\. Use the original\. yang\_2025/puchalski\_He ~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "puchalski_He", "material": "He", "file": "He/yang_2025__puchalski_He.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "reproduced", "reproduced_from": [ "puchalski_2016", "pachucki_2019", "puchalski_2020" ], "uncertainty": { "column": true, "level": "1 sigma" } } Table I 'Theoretical \[8,14,24\]'\: 0\.51725408\(5\) cm^3/mol \(A\_2 1\.332465\(5\) x 10^\-4 with the retardation correction of Ref\. 14\)\: Puchalski et al\. 2016 \(puchalski\_2016\), Pachucki and Puchalski 2019 \(pachucki\_2019\), Puchalski et al\. 2020 \(puchalski\_2020\)\. The A\_eps is puchalski\_2020/molar\_polarizability\. yang\_2025/gaiser\_2018\_He ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "gaiser_2018_He", "material": "He", "file": "He/yang_2025__gaiser_2018_He.csv", "table": "tbl_ca4a321ccfce", "quantity": "molar_refractivity", "unit": "cm3/mol", "abscissa_unit": "nm", "use": "reproduced", "reproduced_from": [ "gaiser_2018" ], "uncertainty": { "column": true, "level": "1 sigma" } } Table I 'Experimental \[17\]'\: 0\.517254\(1\), gaiser\_2018's helium value rounded\. Formulas -------- yang\_2025/ne\_cauchy ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "ne_cauchy", "material": "Ne", "equation": "Eq. (4), p. 2, with Table I, p. 6", "printed": "A_R(nu) = A_eps + A_2 nu_bar^2 + A_4 nu_bar^4 + A_6 nu_bar^6 + A_mu; Ne this work: A_eps 0.994709(8) cm^3/mol, A_2 2.46000(8) x 10^-4 cm^3/mol", "variable": "nu_bar = nu/(10^14 Hz), nu the optical frequency; A_R in cm^3/mol", "state": "none (molar, zero density)", "density": "none", "range": "the two measurement frequencies, 194.4 and 473.6 THz (1542-633 nm), about 303 K", "coefficients": { "A_eps": "0.994709", "A_2": "2.46000e-4" }, "check": "A_2 corresponds to S(-4) = 2.84906 au, against lesiuk_2020's alpha_2 = 2.850(7) (0.03 %); the theory row of Table I prints A_2 = 2.461(5) x 10^-4 (2.85022 au). A_4, A_6 and A_mu are not printed: the formula is incomplete without the authors' assumed values (Lesiuk et al. 2020). Checked 2026-09-25." } The measurement result is the pair \(A\_eps, A\_2\) with the theoretical A\_4, A\_6 and A\_mu; A\_eps is extracted as the dataset A\_eps\_Ne\. yang\_2025/ar\_cauchy ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "ar_cauchy", "material": "Ar", "equation": "Eq. (4), p. 2, with Table I, p. 6", "printed": "A_R(nu) = A_eps + A_2 nu_bar^2 + A_4 nu_bar^4 + A_6 nu_bar^6 + A_mu; Ar this work: A_eps 4.14070(3) cm^3/mol, A_2 24.1320(8) x 10^-4 cm^3/mol", "variable": "nu_bar = nu/(10^14 Hz); A_R in cm^3/mol", "state": "none (molar, zero density)", "density": "none", "range": "194.4 and 473.6 THz (1542-633 nm), about 303 K", "coefficients": { "A_eps": "4.14070", "A_2": "24.1320e-4" }, "check": "A_2 corresponds to S(-4) = 27.9486 au, 0.10 % below lesiuk_2023's 27.976(15) (1.8 sigma of theory); Table I's theory A_2 is 24.16(1) x 10^-4. 'For argon dispersion, measurement and ab initio calculation barely agree within mutual expanded uncertainty' (abstract). Checked 2026-09-25." } A\_4, A\_6, A\_mu assumed from Lesiuk and Jeziorski \(2023\) and ab initio A\_mu \(not printed\)\. yang\_2025/n2\_cauchy ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "n2_cauchy", "material": "N2", "equation": "Eq. (4), p. 2, with Table I, p. 6", "printed": "A_R(nu) = A_eps + A_2 nu_bar^2 + A_4 nu_bar^4 + A_6 nu_bar^6 + A_mu; N2 this work: A_eps 4.38692(3) cm^3/mol, A_2 25.997(5) x 10^-4 cm^3/mol", "variable": "nu_bar = nu/(10^14 Hz); A_R in cm^3/mol", "state": "none (molar, zero density)", "density": "none", "range": "194.4 and 473.6 THz (1542-633 nm), about 303 K", "coefficients": { "A_eps": "4.38692", "A_2": "25.997e-4" }, "check": "A_2 corresponds to S(-4) = 30.1086 au, equal to nie_2025's Olney value 30.11(9); Kumar and Meath's A_2 in Table I, 25.70 x 10^-4 (29.765 au), is 1.1 % lower. Checked 2026-09-25." } A\_4 and A\_6 from Kumar and Meath's DOSD sums \[22\]; the frequency dependence of B\_R set to zero \('a complete lack of knowledge', p\. 5\), which leaves a trend in A\_2\(p\); A\_mu for N2 not final\. Uncertainty of A\_2 2\.0e\-4 of itself \(p\. 6\)\. yang\_2025/he\_A2 ~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "he_A2", "material": "He", "equation": "Eq. (4), p. 2, with Table I, p. 6", "printed": "He this work: A_2 1.332468(6) x 10^-4 cm^3/mol (A_eps fixed to theory, 0.51725408(5))", "variable": "nu_bar = nu/(10^14 Hz); A_R in cm^3/mol", "state": "none (molar, zero density)", "density": "none", "range": "194.4 and 473.6 THz (1542-633 nm), about 303 K", "coefficients": { "A_2": "1.332468e-4" }, "check": "Theory (Table I, Refs. 8, 14, 24, with the retardation correction): 1.332465(5) x 10^-4; the measurement agrees to 2.3e-6 of A_2. S(-4) = 1.543206 au. Checked 2026-09-25." } Solved with epsilon\_p = 0 \(to avoid circularity\) and A\_eps set to the ab initio value \(p\. 6\)\. 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.