摘要:

AbstractA number of qualitative and semi‐quantitative theories is described which relate the self‐diffusion coefficient to other molecular properties or properties of the liquid. In the second part of the article particular emphasis is given to the problem to relate self‐diffusion to the structure of the l

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750302

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractThe self‐diffusion coefficients of three important liquids benzene, water and argon as reported in the literature vary widely. Recent developments designed to improve this situation are described and an assessment made of the best self‐diffusion values for each in the light of all the evidence availa

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750303

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractOn a essayé de mettre en évidence les interactions entre la Sérum Albumine Humaine et les ions zinc et calcium par mesure des coefficients de self‐diffusion des espèces en présence dans le milieu réactionnel.On a employé la méthode du tube capillaire. Les mesures sont faites à 25°C et 37°C en milieux tampons de différentspH. On a pu relier la mesure des coefficients de self‐diffusion an calcul de v, le nombre moyen de cations métalliques liés par mol

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750304

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractSome examples of liquid diffusion cascades for the enrichment of isotopes are presented. The results are discussed in terms of diffusion times and separation factors.

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750305

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractCurrent theories of rotational correlation times in liquids are discussed and examples of the application of the quasilattice random flight model to several polar and nonpolar liquids and electrolytic solutions are given.

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750306

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractBy NMR‐Spin‐echo technique the self‐diffusion coefficients in aqueous solutions of a number of ions and of water have been measured. Measurements have been performed as a function of the concentration of the dissolved salt and of the temperature. Water (H2O) and heavy water (D2O) have been used as solvents. Only in the case of H2O, however, the self‐diffusion of the solvent has been measured. The following liquid systems have been studied in detail: LiClH2O (D Li +,DH2O); Li2SiF6H2O (D Li +,D SiF 6 −,DH2O; [(CH3)4X]2YF6D2O with X  N, P, As, Sb, and Y  Si, Ge (D(CH3)4X+,DYF6−). At various concentrations the self‐diffusion coefficients of the ions and of the water as a function of the temperature may be described by an Arrhenius law. At constant concentration in some cases two different activation energies (frequency factors resp.) occur, one for an upper, the other for a lower temperature range. The result of the measurements are discussed and partially c

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750307

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractIt is my task to show how nuclear magnetic relaxation experiments can yield information about the molecular motion in liquids. I will begin by considering those relaxation mechanisms which have been of major importance for this purpose. In a second part of my paper I will mention common experimental techniques and finally I will review typical applications of the method.

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750308

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractThe proton spin‐lattice relaxation rate of liquid chloroform was measured in the neat liquid and in CHCl3/CDCl3mixtures over the temperature range – 18° to 47°C. Translational self‐diffusion constants are reported in the same temperature range.The intramolecular proton rate obtained from the isotopic dilution measurements is split into a spin‐rotational part and a contribution from the proton‐chlorine dipolar interaction. The spin‐rotational rate is then evaluated by use of a formula which takes into account the anisotropic rotational diffusion of a symmetric‐top molecule. This equation is derived in a theoretical section. The results show that the diffusion equation provides the correct description for the rotational motion.The intermolecular dipolar proton‐proton relaxation rate obtained from the dilution experiments is used to check current theories. None of these describes the experimental results adequately. Various reasons for this fail

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750309

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractThe nuclear magnetic spin‐lattice relaxation time,T1, of 1,4‐paradioxane in deuterated 1,4‐paradioxane, deuterated chloroform, deuterated cyclohexane, deuterated benzene, and carbon tetrachloride was determined as a function of concentration and temperature over the temperature range of 10°C – 100°C. It was found that the rotational correlation time of the p‐dioxane molecule in infinitely dilute CDCl3solution was significantly longer than in the other four solvents. In particular it was found that when the rotational correlation time of the p‐dioxane molecule measured at 20°C in CDCl3solution was‐corrected for the difference in the viscosities of CDCl3and p‐dioxane there resulted a corrected rotational correlation time of 17·10−12s. This value is in fair agreement with the dielectric relaxation time of the CHCl3molecule in infinitely dilute p‐dioxane solution reported by Antony and Smyth [1], viz. 16.5 · 10−12sat 20°C. It was also found that the activation energy for molecular reorientation, ΔEτof the p‐dioxane molecule in infinitely dilute CDCl3was significantly higher than the activation energy for viscous flow, ΔEηin CHCl3, viz. 2.6 kcal/mol and 1.8 kcal/mol respectively. On the other hand it was found that in the case of the other four solvents ΔEτ, ≤ ΔEeta. It is suggested that the experimental results are best interpreted in terms of the formation of a complex between p‐dioxane and CDCl3mo

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750310

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY

摘要:

AbstractPulsed NMR studies to measureT1of35Cl and19F for a sample of neat ClO3F over the entire liquid range (130 to 368 K) were carried out. The chlorine nucleus is relaxed entirely by the quadrupole interaction and sincee2qQ for25Cl is known it is possible to determine experimentally the correlation time for molecular orientation τ0,2. The fluorine relaxation is dominated by the spin‐rotation interaction. WithT1data for19F and an independent knowledge of the effective spin‐rotation constant, the angular momentum correlation time τJcan be determined experimentally. The results for this quasi spherical model are in accord with rotational diffusion theory and Hubbard's relation. τΘ,2τJ= 1/6k T, at temperatures near the melting point and they agree over the entire liquid range with the extended treatment of

ISSN:0005-9021    

DOI:10.1002/bbpc.19710750311

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1971

数据来源: WILEY