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Experimental Results on the Dynamic Polarisation in a Solid by Variation of Temperature
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| Zeitschriftentitel: | Zeitschrift für Naturforschung A |
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| Personen und Körperschaften: | |
| In: | Zeitschrift für Naturforschung A, 28, 1973, 1, S. 98-104 |
| Format: | E-Article |
| Sprache: | Unbestimmt |
| veröffentlicht: |
Walter de Gruyter GmbH
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| Schlagwörter: |
| Zusammenfassung: | <jats:p>A description of the apparatus for a new dynamic polarization effect by variation of temperature, and the experimental results obtained, are presented. As described earlier a temperature jump produces a very large enhancement of the dipolar signal (about 10.000) in solid y-picolene due to the dipolar couplings between the protons of the CH<jats:sub>3</jats:sub>-group and the modes of the CH<jats:sub>3</jats:sub>-rotator with the crystal phonons. A simple phenomenological model for the interpretation of the experimental data is introduced. Within the experimental errors agreement between model and data is obtained.</jats:p><jats:p> From the shape of the measured polarization curves a dipolar polarization time T<jats:sub>p</jats:sub> and the dipolar relaxation time T<jats:sub>d</jats:sub> is determined. From the maxima of the polarization at different temperature jumps a curve dependent only on the temperature is constructed, which together with T<jats:sub>p</jats:sub> and T<jats:sub>d</jats:sub> characterizes completely the dynamic polarization behaviour.</jats:p><jats:p> A comparison of the Zeeman- and dipolar relaxation with earlier measurements on similar molecules containing CH<jats:sub>3</jats:sub>-groups shows that the CH<jats:sub>3</jats:sub>-rotation in solid y-picolene is almost unhindered and that the "relaxation efficiency" is very low. These last conditions are important for a large enhancement of the dipolar polarization.</jats:p> |
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| Umfang: | 98-104 |
| ISSN: |
0932-0784
1865-7109 |
| DOI: | 10.1515/zna-1973-0117 |