burns_1986#

R. C. Burns, C. Graham and A. R. M. Weller, “Direct measurement and calculation of the second refractivity virial coefficients of gases”, Mol. Phys. 59, 41 (1986)

Source record · Catalogue · Review register

DOI: 10.1080/00268978600101901

Source kind: measurement

Recorded technique: The differential decompression method of Buckingham, Cole and Sutter on the apparatus of Buckingham and Graham (1974), moved to Natal: a vibration-compensated interferometer (stability better than 1e-3 fringe) compares a reference beam with a beam through two matched cells A and B; the phase change when gas in A expands into the evacuated B gives B_n (Eq. 2.3), and two successive decompressions cancel the cell mismatch. A_n from separate absolute refractive-index measurements, several hundred fringes counted, phases to better than 1e-2 fringe, MKS Baratron pressures (+-0.05 %), water-jacket temperature to +-0.05 K, densities from Dymond and Smith’s second virial coefficients. He-Ne 632.8 nm and argon-ion 514.5, 488.0 and 457.9 nm (pp. 42-46).

Materials in structured entries: Ar, CH4, CO2, He, Kr, N2, Ne, SF6, Xe

Dataset quantities: molar_refractivity, refractivity_virial_coefficient

Contents: 44 datasets; 0 formulas.

Curation notes#

Page numbers are the journal’s (41-64); pdf page 1 is a cover, so p. = pdf page + 39.

Definitions (p. 41, Eq. 1.1): R_m = (n^2 - 1)/((n^2 + 2) rho) = A_R + B_R rho + ..., rho in mol per volume, so A_R is the package’s molar refractivity and B_R its refractivity_virial_coefficient; A_R = 2 A_n/3 and B_R = 2 B_n/3 - A_n^2/9 (Eqs. 2.4-2.5). Units: Table 2 prints 10^6 A_R/m^3 mol^-1 (= cm^3/mol) and Table 3 10^12 B_R/m^6 mol^-2 (= cm^6/mol^2).

Temperature: not stated with Tables 2 and 3; Tables 6 and 12 compare the 632.8 nm observed values ‘at room temperature (298.2 K)’ (pp. 58, 63), which the B_R datasets take (achtermann_1991 lists them at 298 K).

Wavelengths: the laser lines’ conventional labels, 632.8 nm (He-Ne) and 514.5, 488.0, 457.9 nm (Ar+), which are air wavelengths (the He-Ne line is 632.99 nm in vacuum; quoted from memory, not from a library source): standard_air. The difference changes A_R by about 1e-5 of itself.

Uncertainties (p. 46): A_R, ‘For each gas at least three separate measurements were made at each wavelength. In all cases the standard deviation was less than 0.1 per cent’ (taken as one sigma; pressure +-0.05 %). B_R (p. 46): ‘the quoted uncertainties are obtained by taking the sum of three uncertainties, namely the standard deviation, the variation in B_R due to a +-30 per cent error in the calculated correction for the effects of cell distortion due to gas pressure, and an uncertainty due to drift in the end-point after a decompression. In most cases the standard deviation accounts for roughly half the quoted uncertainty.’ The per-point column is that sum (level not a standard one: ‘not stated’). The authors report ‘evidence of a possible wavelength dependence of B_R’ (abstract, pp. 46-47) beyond the dispersion of alpha, which theory does not predict; B_R of Xe falls from 25.5 at 632.8 nm to 14.9 at 488.0 nm.

The literature values in parentheses in Tables 2 and 3 are extracted as reproduced datasets. Table 2 references: [9] Buckingham and Graham, Proc. R. Soc. A 336, 275 (1974); [12] St-Arnaud and Bose, J. Chem. Phys. 65, 4854 (1976); [19] cuthbertson_1932; [20] cuthbertson_1914 (printed 1913); [21] ‘Proc. R. Soc. A 88, 13 (1910)’, which is cuthbertson_1910 (volume 84) by page and year; [22] dalgarno_1960 (a calculation); [23] watson_1936; [27] cuthbertson_1920; [28] C. and M. Cuthbertson, Proc. R. Soc. A 83, 151, 171 (1909), not in the library. Table 3: [9], [12], [14] St-Arnaud and Bose, J. Chem. Phys. 71, 4951 (1979), [15] Coulon, Montixi and Occelli, Can. J. Phys. 59, 1555 (1981).

Tables 6 and 12 give the calculated B_R (classical dipole-induced-dipole theory with Lennard-Jones 6:12 potentials and, for the atoms and CH4, the C-tensor term; for CO2 and N2 the quadrupole and shape terms, without the C-tensor), extracted as ‘check’ datasets. Not extracted: the fluorinated methanes (not curated species), Table 4 (NH3, Beaume and Coulon), Table 5 and 11’s alpha(nu) (derived from this work’s A_R at 632.8 nm, via Burns’s thesis) and other molecular inputs, Tables 7 and 8 (the sensitivity of the calculation to the potential).

Reproductions elsewhere: achtermann_1991’s A_R_burns_1986_{CH4,CO2,SF6,N2,Ar}, B_R_burns_1986_298_{CO2,SF6,N2,Ar}, B_R_burns_1986_unknown_CH4 and B_R_theory_burns_1986_298_{CH4,CO2,SF6,N2,Ar}; egan_2019’s burns_1986_Ne and burns_1986_Xe (A_R at 633 nm).

Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.