| | 2 | Author
| Heinrich-Schramm, W. E. Price, H.-D Lüdemann | Requires cookie* | | | Title
| A  | | | | Abstract
| Self-diffusion in ethanol/hexane and dimethylether/hexane mixtures of various compositions has been measured at 215-350 K and up to 200 MPa. Qualitative analysis of the results indicates that, as expected, hydrogen bonding retards the self-diffusion of ethanol in the mixture, especially at the low temperatures. Dimethylether shows a slight effect of dipole-dipole interactions on the self-diffu sion, as seen by a higher AE* value than for the alkane. However there is no significant difference in the pressure dependence for both mixtures. This is shown by considering the ratio of the two diffusion coefficients, which suggests that, contrary to what is observed for pure alcohols, pressure has little effect upon the hydrogen bonding of ethanol in the mixture. In additon, there is surprisingly little concentration dependence on the ratios for either mixture. | | | |
Reference
| Z. Naturforsch. 50a, 149—154 (1995); received October 5 1994 | | | |
Published
| 1995 | | | |
Keywords
| Binary mixtures, Self diffusion, High pressure | | | |
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| default:Reihe_A/50/ZNA-1995-50a-0149.pdf | | | | Identifier
| ZNA-1995-50a-0149 | | | | Volume
| 50 | |
| 3 | Author
| Roman Goc | Requires cookie* | | | Title
| Calculation of the NMR Second Moment for Solid Benzene with Rotation and Diffusion of Molecules -Numerical Approach | | | | Abstract
| Numerical calculations of the NMR second moment in case of rotation and diffusion of molecules were performed. As an example computer simulations of molecular reorientation and self-diffusion in solid benzene have been performed. For each model and rate of motion the Van Vleck's second moment of the proton NMR absorption spectrum was calculated, and these values were compared with experimental data. It is concluded that restricted self-diffusion must be implied in order to obtain better agreement between calculated and experimental NMR second moments. The temperature at which self-diffusion was detected through NMR line-width narrowing was found to be about 120 K, nearly 80 K less than the temperature at which the self-diffusion was detected by T lp relaxation measurements. | | | |
Reference
| Z. Naturforsch. 52a, 477—184 (1997); received March 29 1997 | | | |
Published
| 1997 | | | |
Keywords
| NMR, molecular rotation, self-diffusion, numerical approach | | | |
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| default:Reihe_A/52/ZNA-1997-52a-0477.pdf | | | | Identifier
| ZNA-1997-52a-0477 | | | | Volume
| 52 | |
| 5 | Author
| C. Herdlicka, J. Richter, M. D. Zeidler | Requires cookie* | | | Title
| Self-Diffusion in Molten Lithium Nitrate | | | | Abstract
| Self-diffusion coefficients of 7 Li + ions have been measured in molten LiN0 3 with several com-positions of 6 Li + and 7 Li + over a temperature range from 537 to 615 K. The NMR spin-echo method with pulsed field gradients was applied. It was found that the self-diffusion coefficient depends on the isotopic composition and shows a maximum at equimolar ratio. At temperatures above 600 K this behaviour disappears. | | | |
Reference
| Z. Naturforsch. 47a, 1047—1050 (1992); received July 16 1992 | | | |
Published
| 1992 | | | |
Keywords
| Molten salts, Self-diffusion, Isotope effect, NMR spin-echo | | | |
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| default:Reihe_A/47/ZNA-1992-47a-1047.pdf | | | | Identifier
| ZNA-1992-47a-1047 | | | | Volume
| 47 | |
| 6 | Author
| Hiroyuki Ishida, Masakazu Kato, Hiroshi Ono, Ryuichi Ikeda | Requires cookie* | | | Title
| Cationic Self-diffusion in Solid Choline Perchlorate Studied by NMR | | | | Abstract
| The 1 H spin-lattice and spin-spin relaxation times, and the second moment of the 1 H NMR linewidth of choline Perchlorate, [(Cff^NCfFCHiOHJClC^, were measured in its highest-temperature solid phase, i. e. above 275 K. X-ray powder patterns taken at ca. 380 K revealed that in this phase the crystal has a CsCl-type cubic structure (a = 6.326(4) A and Z = 1). From *H NMR experiments it was found that the cations in this phase undergo isotropic rotation and translational self-diffusion. From the 1 H T, measurements, the activation energies of the cationic rotation and self-diffusion were evaluated to be 21.4 ± 0.4 and 62 ± 3 kJ mol -1 , respectively. | | | |
Reference
| Z. Naturforsch. 52a, 637—639 (1997); received May 28 1997 | | | |
Published
| 1997 | | | |
Keywords
| Ionic plastic phase, Self-diffusion, Crystal structure, Nuclear magnetic resonance | | | |
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| default:Reihe_A/52/ZNA-1997-52a-0637.pdf | | | | Identifier
| ZNA-1997-52a-0637 | | | | Volume
| 52 | |
| 7 | Author
| Mineyuki Hattori, Yoshito Onoda, Tomoki Erata, M. E. Smith, Bruker Analytische, M. Esstechnik, G. M. Bh, Masakazu Hattori, Hiroshi Ohki, Ryuichi Ikeda | Requires cookie* | | | Title
| Ionic motion and Disordered Structure in the Rotator Phase of Butylammonium Chloride Studied by Temperature Dependences of 35C1 and 2HNMR | | | | Abstract
| Temperature dependences o f 35C1 and 2H quadrupole coupling constants and 35C1 N M R spin-lat tice relaxation times in polycrystalline samples were measured in the rotator phase of the butylam m onium chlorides C 4H 9N H 3C1 and C4H 9N D 3C1, obtainable above the phase transition tempera ture o f 241 K. A rapid decrease o f the quadrupole coupling constants of both nuclei upon heating is attributed to increasing dynam ic disorder formed around the polar head. The presence of self-dif-fussion o f C P ions was revealed from the spin-spin relaxation time and resonance line-width in single crystals, and confirmed by measuring the dc electrical conductivity. | | | |
Reference
| Z. Naturforsch. 49a, 291 (1994); received July 23 1993 | | | |
Published
| 1994 | | | |
Keywords
| Solid N M R, Quadrupole coupling constant, Spin-lattice relaxation time, Self-diffusion, Rotator phase | | | |
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| default:Reihe_A/49/ZNA-1994-49a-0291.pdf | | | | Identifier
| ZNA-1994-49a-0291 | | | | Volume
| 49 | |
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