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. 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.

2 ,,, 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. 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 . gives Diffusion Coefficients over a very extensive temperature range. from verv low temDeratures to 10000 K.

3 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. 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.

4 Diffusion collision integrals for short range 14 c. Combination .. 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 .. 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.

5 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. 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. molecular beam .. 117 1. Ma9Sa" ~ Institute of T""hnology (Amdur et al.).. 117 2.

6 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 .. 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!}

7 ' .. 12. Correlation parameters of eq ( ) for ~12";"""'" 13. Correlation parameters of eq ( ) for ~12"'''''''''' 14. Classicallow temperature asymptotic values of &112, eq( ) .. , .. 15. Correlation parameters for the compollition depend ence 9f Ed,. according to eq ( ) .. 16. Experimental determinations of ~12 according to gas pair, temperature noted .. a. Noble gases .., .. ' b. Noble gases and another component .. c. Dissociated gases .. d. Other mixtures .. J. Phys. Chem. Ref. Data, Vol. 1, , 1972 34 35 35 36 37 87 87 90 94 95 Page 17. Selected high'temperature points for curve fitting, group 38 lB. molecular beam potentials, ",'(r) KIT", for group 46 19. Values of ~,;by direct measurement compared with those from mixture viscosity, and from thermal .. 47 20. Diffusion Coefficients and weights for curve fitting, group 48 21. molecular beam potentials, ip(r) Klr', for group II .. , .. , .. ,.. 49 22. Diffusion Coefficients and weights for curve fitting, 11l' 77 23.

8 molecular beam potentials, <p(r) = KiT", for group .. 80 24. Diffusion Coefficients and weights for' curve-fitting, miscellaneous .. 86 25. molecular Leam potentials, !p(r) = Klr, for miscellaneous .. 87 List of Figures Figure 1. Qualitative temperature dependence of Diffusion Coefficients .. 11 2. Principal experimental methods for Diffusion .. 19 3. Composition dependence of ~'2 at two mass ratios (m). Equation ( ) is the exact formula of the Chapman Enskog theory; eq ( ) is the semi empirical expressioll of this 32 4: Estimated uncertainty limits of 9'2 as a function of 34 The following figures present the deviations of experimental values of &1'2 from the reference equation for gas pairs in the following sequence: Figure 5. He Ne 6. He Ar 7. He Ar B. He Ar 9. He Ar 10. He-Kr 11. He Xe 12. Ne Ar Figure :ll. "He-'He 22. 3He 4He 23. He N. 24. He Nt 25. He CO Group I Page 38 39 39 40 40 41 41 42 Group II Page :>u 50 51 51 :12 Figure 13.

9 Ne-Kr 14. Ne Xe 15. Ar-Kr 16. Ar Xe 17. Kr-Xe 18. H,-N2 19. H2 N2 20. H. N. Figure 26. He-O, 27. He air 28. Btl, CO2 29. He:C02 go. q~ Page 38 43 43 44 44 45 45 46 Page 52 53 53 54 :>4 Gaseous Diffusion Coefficients 5 Figure Page }'igure Page 3l. H2 Nc 55 39. H2 air 59 32. H. Ar 55 40. Hz'CO. 59 33. H. Ar S6 4L H. C02 60 34. H2 Kr 56 42. Nz Ar 60 35. H. D. 57 43. N2'CO 61 36. H. D. 57 44. N. CO 61 37. H2 D. 5& 45. N. CO. 62 38. Hz'CO 58 46. N2'CO. 62 Group III Figure Pag. Figure Page 47. , 64 61. N. Kr 71 48. Ar CO 6S 62. N. Xe 72 49. Ar O. 6S 63. NrO. 72 50. Ar C02 66 64. N. SFs 73 51. Ar SFs 66 65. CO Kr 73 52. Hz Xe 67 66. CO O. 74 53. H. CIL. 67 67. CO C02 74 54. H. O. 68 68. CO C02 75 55. H2 SF6 68 69. CO SFs 75 56. ClLl'He 69 70. o. C02 76 ';)'1. CH. N2 69 71. 02 5Fs 76 58. C~ 02 70 72. CO2 air 77 59. CH4 SFs 70 73; CO. N2O 77 60. N2 Ne 71 74. CO. SFs 78 75. He'!SJ.'s 78 Miscellaneous Systems Figure Pag. Figure Page 76. 8'1 79 .. 84 77.

10 H20 02 83 80. CO2 Ne 85 78. H2O air 84 81. CO2 CaHa 85 1. Introduction The purpose of this report is to evaluate pub-lished data on Gaseous Diffusion Coefficients and establish recommended values when possible. Short catalogs of measured Diffusion Coefficients have previously appeared in the International Critical T~bles [1],1 the Landolt Bornstein Tables f2], and the Thermophysical Properties Research . Literature Retrieval Guide [3]. Additional limited reviews are also available [4-81_ In the present survey Gaseous Diffusion Coefficients are compre-hensively compiled and critically evaluated, including analysis for consistency with theory and with other measured molecular properties. Such detailed evaluation is possible because of the exist-ence of a highly developed theory for dilute gases. The scope of this survey is therefore limited to the dilute gas region. In this region the density is such that the rates of transport of mass, momentum, and l energy are entirely controlled by binary molecular collisions.