Pulsed NMR Studies of Fluorine Relaxation in MPF6.
ILLINOIS UNIV URBANA DEPT OF CHEMISTRY AND CHEMICAL ENGINEERING
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The fluorine spin-lattice relaxation time t1 was studied in polycrystalline Na, K, Rb, and Cs hexafluorophosphates at temperatures between 77 and 476K by pulsed NMR methods. In each case a discontinuity occurs in the temperature dependence, at 276, 275, 210 and 82K, respectively, those for the K and Rb salts corresponding to previously reported phase transitions. The temperature dependence of T1 observed in the low-temperature phase of the NA, K and Rb salts has a minimum and an asymmetric shape. In the high-temperature phase of all four salts, T1 exhibits a broad frequency-independent maximum of 4 to 7 sec which is attributed to relaxation by spin-rotation interactions within the rapidly reorienting PF6- ions. Author Modified Abstract
- Physical Chemistry