Chlorine Nuclear Spin-Spin Relaxation Mechanism in Mg(H2O)6SnCl6 as Studied by NQR and NMR Techniques

1992 ◽  
Vol 47 (1-2) ◽  
pp. 277-282 ◽  
Author(s):  
Keizo Horiuchi ◽  
Daiyu Nakamura
Keyword(s):  
Relaxation Time ◽  
Spin Relaxation ◽  
Lattice Relaxation ◽  
Relaxation Mechanism ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Local Magnetic Field ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Increasing Temperature

AbstractThe 35Cl NQR spin-lattice relaxation time T1Q, spin-spin-relaxation time T2Q, and 1H NMR spin-lattice relaxation time in the rotating frame T1Q in Mg(H2O) 6SnCl6 were measured as functions of temperature. Above room temperature T2Q increased rapidly with increasing temperature, which can be explained by fluctuations of the local magnetic field at the chlorine nuclei due to cationic motions. From the T1Q experiments, these motions are found to be attributable to uniaxial and overall reorientations of [Mg(H2O)6 ] 2 + ions with activation energies of 95 and 116 kJ mol - 1 , respectively. Above ca. 350 K, T1Q decreased rapidly with increasing temperature, which indicates a reorientational motion of [SnCl6] 2 - ions with an activation energy of 115 kJ mol -1 .

scholarly journals Temperature dependence of the Spin-Lattice Relaxation Time of the 23Na-NMR Line in NaNO2

1992 ◽  
Vol 47 (1-2) ◽  
pp. 313-318 ◽  
Author(s):  
M. Igarashi ◽  
H. Kitagawa ◽  
S. Takahashi ◽  
R. Yoshizaki ◽  
Y. Abe
Keyword(s):  
Relaxation Time ◽  
Temperature Dependence ◽  
Lattice Relaxation ◽  
Polycrystalline Sample ◽  
Relaxation Mechanism ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
23Na Nmr

AbstractThe spin-lattice relaxation time, T1, of the 23Na-NMR line in NaNO2 is measured between 25 K and 160 K at two magnetic field strengths, 1.1 T and 6.9 T. The temperature dependence of T1 for the center line, observed on a polycrystalline sample prepared by precipitation from aqueous solution, is given by a monotonous curve. T1 increases gradually as the temperature decreases. On the other hand for a single crystal, which is made by a modified Bridgman method, the temperature dependence of T1 shows two deep dips below 150 K and a frequency dependence which cannot be explained by ordinary BPP theory. The dominant relaxation mechanism above and below 150 K is also investigated.

NUCLEAR SPIN-LATTICE RELAXATION TIME IN TIN

1978 ◽  
Vol 39 (C6) ◽  
pp. C6-1215-C6-1216
Author(s):  
H. Ahola ◽  
G.J. Ehnholm ◽  
S.T. Islander ◽  
B. Rantala
Keyword(s):  
Relaxation Time ◽  
Nuclear Spin ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation

Pressure dependence of iodine nuclear relaxation in rubidium iodide

1978 ◽  
Vol 56 (10) ◽  
pp. 1386-1389
Author(s):  
Marie D'Iorio ◽  
Robin L. Armstrong
Keyword(s):  
Relaxation Time ◽  
Lattice Relaxation ◽  
Low Pressure ◽  
Lattice Relaxation Time ◽  
Lattice Defects ◽  
Spin Lattice Relaxation ◽  
Polymorphic Phase Transition ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Pressure Phase

The pressure-induced polymorphic phase transition at about 4 k bar in rubidium iodide was studied using nuclear magnetic resonance. The signature of the structural transition is a loss of echo intensity which presumably is due to an increase in the number of lattice defects as a result of the transition. The ratio of the spin–spin relaxation times of the iodine nuclei in the two phases is in agreement with the ratio predicted by a second moment calculation. The actual experimental values, however, are considerably smaller than the theoretical predictions signifying the migration of lattice defects. Estimates of the iodine spin–lattice relaxation time at atmospheric pressure indicate the necessity to include both an anharmonic Raman contribution and a covalency factor. The change in spin–lattice relaxation time with pressure as measured in the low pressure phase is dominated by the change in the lattice parameter. At the critical pressure the spin–lattice relaxation time decreases by a fractional amount which is approximately equal to the fractional volume change characterizing the transition. The pressure derivative of the spin–lattice relaxation time in the high pressure phase is nearly equal to that in the low pressure phase.

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