Proton Magnetic Resonance Study of Molecular Motion in Solid Silver Sulfate Tetrammine, Ag2S04 • 4NHS
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چکیده
The spin lattice relaxation time T\ and the second moment of the proton magnetic resonance were studied on polycrystalline samples of Ag2S04 • 4NH3. The wideline NMR measurements show a rapid reorientation of the NH3 groups around their threefold axes in the temperature range 250 K ^ T ^ 380 K. Below T 250 K, the rotation of the NH3 starts freezing-in. From Ti measurements an activation energy of 27.5 kJ mol-1 for the rotation was found for temperatures above 210 K. Around 330 K a phase transition has been observed by Ti measurements which is not recognized by wideline NMR measurements in the range 77 K sS T ^ 375 K. The results are discussed and compared with other NMR studies on solids containing NH3 groups.
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تاریخ انتشار 2012