Self-diffusion and density of liquid hexafluorobenzene as a function of pressure and temperature

Hogenboom, D. L.; Krynicki, K.; Sawyer, David W.

doi:10.1080/00268978000101911

Cited by 23 publications

(9 citation statements)

References 31 publications

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“…which provides a definition for the n-dependent close-packed packing fraction. Rearrangement of eqn (12) to,…”

Section: àAmentioning

confidence: 99%

“…for transport coefficient, X, 12 where A i are constants that can be fitted to a given set of experimental data. In the colloid literature, the Krieger-Dougherty formula and variants of it are used to represent the concentration-dependence of the Newtonian shear viscosity, with the generic form, Z s p (1 À z/z 0 ) Àb , where z is the packing fraction, z 0 is a close packed packing fraction, and b is an exponent.…”

Section: Introductionmentioning

confidence: 99%

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Self-diffusion coefficients and shear viscosity of inverse power fluids: from hard- to soft-spheres

Heyes

Brańka

2008

Phys. Chem. Chem. Phys.

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Molecular dynamics computer simulation has been used to compute the self-diffusion coefficient, D, and shear viscosity, eta(s), of soft-sphere fluids, in which the particles interact through the soft-sphere or inverse power pair potential, phi(r) = epsilon(sigma/r)(n), where n measures the steepness or stiffness of the potential, and epsilon and sigma are a characteristic energy and distance, respectively. The simulations were carried out on monodisperse systems for a range of n values from the hard-sphere (n --> infinity) limit down to n = 4, and up to densities in excess of the fluid-solid co-existence value. A new analytical procedure is proposed which reproduces the transport coefficients at high densities, and can be used to extrapolate the data to densities higher than accurately accessible by simulation or experiment, and tending to the glass transition. This formula, DX(c-1) proportional, variant A/X + B, where c is an adjustable parameter, and X is either the packing fraction or the pressure, is a development of one proposed by Dymond. In the expression, -A/B is the value of X at the ideal glass transition (i.e., where D and eta(s)(-1) --> 0). Estimated values are presented for the packing fraction and the pressure at the glass transition for n values between the hard and soft particle limits. The above expression is also shown to reproduce the high density viscosity data of supercritical argon, krypton and nitrogen. Fits to the soft-sphere simulation transport coefficients close to solid-fluid co-existence are also made using the analytic form, ln(D) = alpha(X)X, and n-dependence of the alpha(X) is presented (X is either the packing fraction or the pressure).

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“…which provides a definition for the n-dependent close-packed packing fraction. Rearrangement of eqn (12) to,…”

Section: àAmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Self-diffusion coefficients and shear viscosity of inverse power fluids: from hard- to soft-spheres

Heyes

Brańka

2008

Phys. Chem. Chem. Phys.

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“…[7] between slip and stick boundary conditions. dependence of diffusion coefficients in the liquid phase (37,39,41) and the associated activation energies are then discussed. Alternatively, transport could be described in terms of temperature and molar volume v = l / n without reference to an energy barrier (37,39,(42)(43)(44).…”

Section: Free Volume Modelmentioning

confidence: 99%

“…dependence of diffusion coefficients in the liquid phase (37,39,41) and the associated activation energies are then discussed. Alternatively, transport could be described in terms of temperature and molar volume v = l / n without reference to an energy barrier (37,39,(42)(43)(44). In liquids DM could be fitted to T'" (v -vo)/vo, where vo is the molar volume at which the liquid molecules are too crowded for diffusion to occur (5).…”

Section: Free Volume Modelmentioning

confidence: 99%

“…The value of Dion can be obtained from that of p using the Nemst-Einstein relation (I), Diffusion coefficients can be related to R, the effective radius of the diffusing particle by the Stokes-Einstein relation (39), where the constant S has a value near4 (slip boundary condition) for neutral molecule self diffusion in liquids. For ions in neutral molecular liquids or dense gases the charge particle interacts more strongly with the fluid molecules than does a neutral molecule, so S = 6 (sticking boundary condition) might apply.…”

Section: B Comparison To Neutral Molecule Diffusionmentioning

confidence: 99%

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Density effects on ion mobilities in electron attaching fluids: CS₂, SF₆, and C₆F₆

Gee¹,

Ramanan²,

Freeman³

1990

Can. J. Chem.

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Ion mobilities μ were measured at densities n ranging from those of the low density gas (n < 0.01 nc, where nc = critical fluid density) through the dense gas and low-density liquid transition region (~0.5nc to 2nc) to the normal liquid (~3nc). The mobility at a given density was constant over a 10-fold variation of electric field strength, typically in the range 0.1 < E(MV/m) < 5. In the gas phase changes in mobility were dominated by changes in gas density. Comparison with neutral molecule transport in SF6 was used to illustrate the change in the effect of the ion on its local environment from that of molecular cluster formation to that of liquid electrostriction as density was increased. In the liquid, changes in ion mobility are dominated by changes in free volume. Mobilities in the present liquids could be described without reference to the activation energies suggested by the Arrhenius model. Keywords: ion, mobility, fluid, density, electron attaching.

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NMR Relaxation in Solutions of Six Fluorinated Benzenes Containing a Free Radical

Darges

Müller‐Warmuth

1981

Ber Bunsenges Phys Chem

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H and I9F NMR spin-lattice relaxation times and dynamic nuclear polarization (DNP) enhancements have been measured at various temperatures in a magnetic field of 17 mT for solutions of six polyfluorinated benzenes containing free radicals. From the radical induced relaxation rates and DNP coupling factors, dipolar and scalar hyperfine coupling contributions have been separated. As a result, the dipolar fluorine and the total proton relaxation rates are more or less the same, and they are only controlled by the molecular motion. The scalar relaxation rates depend upon the chemical structure, but their temperature dependence is also given by the process of translational diffusion. The activation energies for molecular translation, and the scalar contact coupling intensity both increase as one goes from mono-to hexafluorobenzene. Coupling mechanisms and comparison with viscous flow and diffusion are discussed.

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Self-diffusion and density of liquid hexafluorobenzene as a function of pressure and temperature

Cited by 23 publications

References 31 publications

Self-diffusion coefficients and shear viscosity of inverse power fluids: from hard- to soft-spheres

Self-diffusion coefficients and shear viscosity of inverse power fluids: from hard- to soft-spheres

Density effects on ion mobilities in electron attaching fluids: CS₂, SF₆, and C₆F₆

NMR Relaxation in Solutions of Six Fluorinated Benzenes Containing a Free Radical

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Self-diffusion and density of liquid hexafluorobenzene as a function of pressure and temperature

Cited by 23 publications

References 31 publications

Self-diffusion coefficients and shear viscosity of inverse power fluids: from hard- to soft-spheres

Self-diffusion coefficients and shear viscosity of inverse power fluids: from hard- to soft-spheres

Density effects on ion mobilities in electron attaching fluids: CS2, SF6, and C6F6

NMR Relaxation in Solutions of Six Fluorinated Benzenes Containing a Free Radical

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Density effects on ion mobilities in electron attaching fluids: CS₂, SF₆, and C₆F₆