Ammonium ion diffusion in the superprotonic phase of (NH4)3H(SO4)2 as studied by 1H spin-lattice relaxation times in the rotating frame

2008 ◽  
Vol 178 (35-36) ◽  
pp. 1792-1797 ◽  
Author(s):  
H OMI
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Ammonium Ion ◽  
Rotating Frame ◽  
Ion Diffusion ◽  
Spin Lattice ◽  
Superprotonic Phase

Hydrogen Isotope Effect on the Temperature Dependence of the 35Cl-NQR Frequency in (NH4)2IrCl6

2002 ◽  
Vol 57 (6-7) ◽  
pp. 504-508 ◽  
Author(s):  
Yoshio Kume ◽  
Tetsuo Asaji
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Ammonium Ion ◽  
Energy Separation ◽  
Rotational States ◽  
Spin Lattice ◽  
35Cl Nqr ◽  
Deuterated Analogue ◽  
Hydrogen Isotope Effect

The 35Cl-NQRfrequencies and spin-lattice relaxation times of (NH4)2IrCl6 and (ND4)2IrCl6 were measured in the temperature range 4.2 - 300 K. It was confirmed that no phase transition takes place down to 4.2 K. The observed frequency at 4.2 K in (ND4)2IrCl6 was higher by 18 kHz than that in the non-deuterated analogue. This discrepancy was attributed to a difference between the lowest rotational states of the ammonium ions in these compounds. The energy separation between the ground state and excited state of rotational motion, in which N-H of the ammonium ion rotates among the three directions slightly apart from the triad axis, was estimated by fitting analysis to be 31 cm-1 and 93 cm-1 for (ND4)2IrCl6 and (NH4)2IrCl6, respectively. The activation energy of the reorientation of the ammonium ion among the four directions of the triad axis was estimated to be 6.9 and 7.6 kJ mol-1, respectively

scholarly journals NMR relaxometry: Spin lattice relaxation times in the laboratory frame versus spin lattice relaxation times in the rotating frame

2010 ◽  
Vol 495 (4-6) ◽  
pp. 287-291 ◽  
Author(s):  
Emilie Steiner ◽  
Mehdi Yemloul ◽  
Laouès Guendouz ◽  
Sébastien Leclerc ◽  
Anthony Robert ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Laboratory Frame ◽  
Spin Lattice Relaxation ◽  
Rotating Frame ◽  
Spin Lattice ◽  
Nmr Relaxometry

Investigation of the H1 Spin-Lattice Relaxation Times of Some Ammonium Compounds

1979 ◽  
Vol 34 (2) ◽  
pp. 239-241
Author(s):  
F. Köksal
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Dipolar Interaction ◽  
Interaction Constant ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Ammonium Ion ◽  
Ammonium Ions ◽  
Reorientational Motion ◽  
Spin Lattice

Abstract The temperature dependence of the proton spin-lattice relaxation times of (NH4)2Al(SO4)2, (NH4)2 MoO4, NH4NH2SO3 and (NH4)2SnCl6 has been investigated in the temperature range 100- 500 K. The experimental results indicate that intra H-H dipolar interaction, modulated by reorientational motion of the ammonium ion, is the dominant relaxation mechanism between 100 and 200 K. The activation energies for the reorientational motion of the ammonium ions were found to be 1.54, 1.56, 0.99, and 0.91 kcal/mole, respectively. Furthermore, it has been detected that above 200 K the spin-rotational interactions of the ammonium ions contribute to the spin-lattice relaxation. The average value of the mean-square spin-rotational interaction constant for NH4+ was found to be C2 = 1.42 × 1010 s-2

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