| | 1 | Author
| S. Lewicki, B. Szafrańska, Z. Pająk | Requires cookie* | | | Title
| Molecular Motion in Solid Tetrapropylammonium Bromide and Iodide  | | | | Abstract
| The proton NMR second moment and spin-lattice relaxation time for tetrapropylammonium bromide and iodide have been measured over a wide temperature range. A solid-solid phase transition related to the onset of cation tumbling was found for both salts and confirmed by DTA. In the low temperature phases methyl group reorientation was evidenced. For iodide a dynamic nonequivalence of the methyl groups and the onset of ethyl groups motion was also discovered. | | | |
Reference
| Z. Naturforsch. 47a, 1115—1118 (1992); received July 14 1992 | | | |
Published
| 1992 | | | |
Keywords
| NMR, Molecular motions, Phase transitions | | | |
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| default:Reihe_A/47/ZNA-1992-47a-1115.pdf | | | | Identifier
| ZNA-1992-47a-1115 | | | | Volume
| 47 | |
| 3 | Author
| S. Torre, P. Ferloni | Requires cookie* | | | Title
| Molecular Motion in Solid Tetramethylammonium Tetrafluoroborate | | | | Abstract
| Measurements of n B and NMR relaxation times, differential scanning calorimetry and thermomechanical analysis, carried out on polycrystalline (CH 3) 4 NBF 4 from room temperature to about 100 K, have permitted to discuss the crystal dynamics of this salt and to analyze the nature of the phase transition occurring at «150K. Moreover, by means of an evaluation of the n B quadrupole coupling constant, information about the position of the F atoms has been obtained. An explanation of the NMR data in terms of an order-disorder phase transition involving the F~ ions is given. | | | |
Reference
| Z. Naturforsch. 47a, 721—727 (1992); received March 24 1992 | | | |
Published
| 1992 | | | |
Keywords
| (CH 3 ) 4 NBF 4, Molecular motion, Phase transition | | | |
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| default:Reihe_A/47/ZNA-1992-47a-0721.pdf | | | | Identifier
| ZNA-1992-47a-0721 | | | | Volume
| 47 | |
| 4 | Author
| Makoto Kaga, Tetsuo Asaji, Ryuichi Ikeda, Daiyu Nakamura | Requires cookie* | | | Title
| Chlorine Nuclear Quadrupole Relaxation and Cationic Motion in Trimethylsulfonium Hexachloroselenate(IV): [(CH 3 ) 3 Sl 2 SeCl^ | | | | Abstract
| The 35 C1 NQR spin-lattice and spin-spin relaxation times, 7^ and T2Q, respectively, and the 'H NMR spin-lattice relaxation time T1H at 32 and 60 MHz were determined for [(CH3j3S]2SeCl6 as functions of temperature. The rapid decrease of observed above ca. 250 K with increasing temperature was attributed to the onset of reorientation of the [SeCl6] 2 " complex anion with the activation energy £a = 42 + 5 kJ mol -1 . When cooled from ca. 250 K, T1Q showed an anomalous decrease. This 7"1Q decrease was explained by electric field gradient modulation related to some cationic motion. Possible origins of the cationic motion are discussed. | | | |
Reference
| Z. Naturforsch. 47a, 274—276 (1992); received July 19 1991 | | | |
Published
| 1992 | | | |
Keywords
| Spin-lattice relaxation, NQR, NMR, EFG modulation, Molecular motion | | | |
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| default:Reihe_A/47/ZNA-1992-47a-0274.pdf | | | | Identifier
| ZNA-1992-47a-0274 | | | | Volume
| 47 | |
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