Effective Collision Cross-Sections for Polyatomic Gases from Transport Properties and Thermomolecolar Pressure Differences

Millat, J.; Plantikow, A.; Mathes, David T.; Nimz, H.

doi:10.1515/zpch-1988-26996

Cited by 11 publications

(5 citation statements)

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“…(5). The agreement with the values inferred from the thermal transpiration measurements 33 is excellent with deviations decreasing monotonically with increasing temperature from +1.2% at 300 K to −0.1% at 600 K.…”

Section: Translational Eucken Factorsupporting

confidence: 79%

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Calculation of the transport and relaxation properties of methane. II. Thermal conductivity, thermomagnetic effects, volume viscosity, and nuclear-spin relaxation

Hellmann

Bich

Vogel

et al. 2009

The Journal of Chemical Physics

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Transport properties of pure methane have been calculated in the rigid-rotor approximation using the recently proposed intermolecular potential energy hypersurface [R. Hellmann et al., J. Chem. Phys. 128, 214303 (2008)] and the classical-trajectory method. Results are reported in the dilute-gas limit for the temperature range of 80-1500 K. The calculated thermal conductivity values are in very good agreement with the measured data and correlations. In the temperature range of 310-480 K the calculated values underestimate the best experimental data by 0.5%-1.0%. We suggest that the calculated values are more accurate, especially at low and high temperatures, than the currently available correlations based on the experimental data. Our results also agree well with measurements of thermal transpiration and of the thermomagnetic coefficients. We have shown that although the dominant contribution to the thermomagnetic coefficients comes from the Wjj polarization in the spherical approximation, the contribution of a second polarization, Wj, cannot be neglected nor can a full description of the Wjj polarization. The majority of the volume viscosity measurements around room temperature are consistent with the calculated values but this is not the case at high and low temperatures. However, for nuclear-spin relaxation the calculated values consistently exceed the measurements, which are mutually consistent within a few percent.

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Section: Translational Eucken Factorsupporting

confidence: 79%

“…For a number of gases Millat et al 33 performed a series of thermal transpiration experiments that allow the determination of the translational Eucken factor, f tr , (see Eq. (5)) and consequently evaluation of the contribution of the translational degrees of freedom to the thermal conductivity.…”

Section: Translational Eucken Factormentioning

confidence: 99%

Calculation of the transport and relaxation properties of methane. II. Thermal conductivity, thermomagnetic effects, volume viscosity, and nuclear-spin relaxation

Hellmann

Bich

Vogel

et al. 2009

The Journal of Chemical Physics

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“…The different averaging (over the rotational states) associated with IRDR compared to other measurements of rotational relaxation in methane, such as the (0001) from sound absorption data, have been discussed by Foy et al 52 The rotational contribution aro,(0001) = 6.5 Á2 was derived from the full cross section (0001) by using the heat capacities for internal rotational and vibrational motion, and also Tvib(0001) from vibrational collision numbers in the literature, in the equation c¡",<t(0001) = crot<rrot(0001) + cvibavib(0001) For details see ref 50, where values for other temperatures (180, 260, and 293 K) are also given.…”

Section: Discussionmentioning

confidence: 99%

Carbon-13 and proton spin relaxation in methane in the gas phase

Jameson¹,

Smith²,

Jameson³

et al. 1991

J. Phys. Chem.

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“…(14) or (15). Since there existed only a limited number of measurements, such as the determination of thermomolecular pressure differences, which allow rotational collisional numbers ζ rot to be deduced [21], Millat et al [14,15] used a relationship by Brau and Jonkman [22] to generate the temperature dependence of ζ rot for the complete temperature range corresponding to that of S(2000).…”

Section: Methodology Of Data Correlationmentioning

confidence: 99%

The Ratio Dint /D between the Coefficients for the Diffusion of Internal Energy and of Self Diffusion in Thermal Conductivity Data Correlations for Gases of Linear Molecules

2005

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Highly consistent sets of generalized cross sections are used to judge critically correlations of the thermal conductivity in the limit of zero density for nitrogen, carbon monoxide, and carbon dioxide. The correlations were developed by Millat, Vesovic, and Wakeham some years ago using restricted experimental information in order to deduce a set of generalized cross sections as consistent as possible for the extrapolation beyond the temperature range of the primary experimental data. Recently, the generalized cross sections needed have been evaluated by means of classical trajectory calculations for rigid rotors on the basis of accurate anisotropic ab initio potential energy hypersurfaces including a new improved way to take into account the vibrational degrees of freedom. It is shown that the ratio between the coefficients of internal energy and of self diffusion D int /D was not appropriately chosen and that this effect was extensively compensated in a fortuitous way in the course of the development of the data correlations by a likewise unsuitable choice of the ratio A * between the effective cross sections of viscosity and self-diffusion.

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Effective Collision Cross-Sections for Polyatomic Gases from Transport Properties and Thermomolecolar Pressure Differences

Cited by 11 publications

References 0 publications

Calculation of the transport and relaxation properties of methane. II. Thermal conductivity, thermomagnetic effects, volume viscosity, and nuclear-spin relaxation

Calculation of the transport and relaxation properties of methane. II. Thermal conductivity, thermomagnetic effects, volume viscosity, and nuclear-spin relaxation

Carbon-13 and proton spin relaxation in methane in the gas phase

The Ratio Dint /D between the Coefficients for the Diffusion of Internal Energy and of Self Diffusion in Thermal Conductivity Data Correlations for Gases of Linear Molecules

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