Gaseous Diffusion Coefficients - NIST

1 Journal of Physical and Chemical Reference Data 1, 3 (1972); , 3 1972 American Institute of Physics for the National Institute of Standards and Diffusion CoefficientsCite as: Journal of Physical and Chemical Reference Data 1, 3 (1972); Online: 28 October 2009T. R. Marrero, and E. A. MasonARTICLES YOU MAY BE INTERESTED INA Viscosity Equation for Gas MixturesThe Journal of Chemical Physics 18, 517 (1950); Properties of Multicomponent Gas MixturesThe Journal of Chemical Physics 17, 550 (1949); Equations to Calculate 16 of the Transport Collision Integrals (l, s)* for the Lennard-Jones (12 6) PotentialThe Journal of Chemical Physics 57, 1100 (1972); DiHusion CoeHicients T.

2 R. Marrero* and E. A. Mason Brown University, Providence, Rhode Island 02912 Diffusion Coefficients of binary mixtures of dilute gases are comprehensively compiled, critically evaluated, and correlated by new semi empirical expressions. There are seventy-four systems for which the data are sufficiently extensive, Cuu~i8tent and itl'curale to allow diiful5iuJI cudlid""l" tu J.,,, recommended with confidence. Deviation plot$ are given for most of these systems' .. Almost every Gaseous Diffusion coefficient which was experimentally determined and reported prior to 1970 can be obtained from the annotated bibliography and table of gas pairs.

3 A detailed analysis of experimental methods is given, and jntercomparison of their results helps establish reliability limits for the data, which depend strongly on temperature. Direct rneal5urernents are supplemented by calculations based on knowledge of intermolecular forces derived from independent sources-molecular beam scattering for high temperatures, and London dispersion constants for low temperatures. In addition, Diffusion Coefficients for several mixtures are obtained from experimental data on mixture viscosities and thermal Diffusion factors. Combination of all these results.

4 Gives Diffusion Coefficients over a very extensive temperature range. from verv low temDeratures to 10000 K. All data are corrected tor composition dependence and .for quantum effects. New semi'empirical equations are derived for making such corrections easily. Key words: Hinary gas miXtures; critically eValuated data; Diffusion ; dlft) Coefficients ; gases; transport properties. Contents Page Page List of 4 a. Mixture 15 List of Figures .. , 4 l.. 5 References for section 6 2. Theoretical .. 6 Phenomenological definition of the Gaseous diffu sion 6 a.

5 Two component .. 6 b. Multicomponent mixtures .. ;.. 7 Molecular theory of 7 a. Generalhackground .. :.. 7 b. Theoretical 8 c. Theoretical .. 9 Temperature dependence of Diffusion Coefficients . 11 a. Long rangeinteractions .. ;: 12 b. Short-range 12 c. Intermediate range .. 12 Composition dependence of Diffusion Coefficients . 12 Quantum effects on Diffusion 13 Determination of Diffusion Coefficients from inter-molecular 14 a. Diffusion collision Integrals for long range 14 b. Diffusion collision integrals for short range 14 c. Combination.

6 15 Determination of Diffusion Coefficients from other transport property measurements.,.. 15 Pr .. nt affiliation: The Babcock & Wilcox Company, Researeh and Develop-ment Division, Lynchburg Center, Lynchburg, Virginia, 24505. 3 b. Mixture thermal 16 c. Thermal Diffusion .. 16 References for section 2 .. 3. Experimental methods for Diffusion Coefficients .. Outline of experimental methods .. Major experimental methods .. a. Closed tube .. _ .. b. Two bulb apparatus .. c. Point source .. d. Gas chromatography .. e. Evaporation tube .. Minor experimental methods.

7 A. Open tube .. : .. b. Back Diffusion .. c. Capillary leak .. d. Unsteady evaporation .. e. Diffusion bridge .. ; .. f. Dissociated gases .. Miscellaneous experimental methods .. a. Droplet evaporation .. b. Dufour effect .. c. Thermal separation rate .. d. Kirkendall effect .. " .. ; .. e. Sound absorption .. f. Cataphoresis .. g. Resonance methods .. References for section 3 .. 4. Treatment of data .. Reliability estimates .. Correction for composition dependence .. Correlation for temperature dependence .. 17 18 19 19 19 21 22 23 25 27 27 28 28 28 28 28 28 28-28 28 29 29 29 29 30 30 30 31 32 J.

8 Phys. Chem. Ref. Data, Vol. 1. 1972 4 T. R. MARRERO AND E. A. MASON P.~e References for section .. 33 5.. 33 Uncertainty .. 33 Correlation param' .. 35 Deviatil)n .. 36 Detailed remarks .. ;.. 37 a. Group I (deviation plots, figs. 5 to 20).. 38 b. Group II (deviation plots, figs. 21 to 46).. 47 c. Group III (deviation plots, figs. 47 to 75).. 63 d. Miscellaneous (deviation plots, figs. 76 to 81).. 82 References for Section .. 110 6. Acknowledgments .. '.. 110 Biblioe;raphy 1. Gaseous Diffusion Coefficients for binary mixtures (1870 to 1970).. 111 II.

9 Molecular beam .. 117 1. Ma9Sa" ~ Institute of T""hnology (Amdur et al.).. 117 2. Moscow State University {Leonas etal.).. 117 3. Other 118 4. Revi .. ws .. III. London dispersion constants .. IV. Related viscosity measurements .. 1. Primary references .. 118 118 118 118 2. Secondary .. 118 List of Tahles Table 1. Quantum effects on Diffusion Coefficients and on collision integral ratio At. in terms of the deBoer parameter, A *, and the reduced temperature, T*=kT/E .. 2. Classification of experimental methods .. 3. Determinations of 9'2 by the closed-tube method.}

10 4. Determinations of 9,. by the two bulb method .. 5. Determinations of 9'2 hy the point-source method .. 6. Determinations of 9'2 by the gas chromatography method .. ,.: .. _ .. 7. Determinations of ~'2 by the evaporation tube 13 18 20 21 22 23 26 8. Determinations of ~'2 by minor experimental 27 9. Determinations of ~12 by miscellaneous experi mental .. 29 10. Grouping of systems according to 'uncertainty limits of ~12"'''' .. 34 n. Uncertainty limits for systems of the miscellaneous grou!' .. 12. Correlation parameters of eq ( ) for ~12";"""'" 13. Correlation parameters of eq ( ) for ~12"'''''''''' 14.