Proton spin lattice relaxation in lithium ammonium sulphate LiNH₄SO₄

7Li Spin-Lattice Relaxation Time in a LiNH4SO4 Single Crystal

“…The activation energies in phases III and II were determined to be 10.93 and 3.68 kJ/mol, respectively. Our observation of changes in the activation energy is consistent with the activation energy obtained from the relaxation times for 1 H by Shenoy and Ramakrishna [8]. These activation energies are shown in Table 1 for the phases II and III.…”

“…Many investigations have been performed on LiNH 4 SO 4 , including dielectric [1 to 3], optical [4,5], thermal [3,6,7], NMR [2,4,5,8], elastic constants [9], Brillouin scattering [10], and pressure studies [3,4,11,12]. Three phases of LiNH 4 SO 4 crystal can be distinguished.…”

Study of the phase transitions by observation of the A and1H nuclear magnetic resonance in ANH4SO4(A =7Li,39K and87Rb) single crystals with excellent optical quality

“…The E a of 1.23 kcal mol −1 obtained from our experimental results [23] in phase III is consistent with the results reported by Watton et al [13]. The trend observed for T 1 below 133 K is similar to that reported for phase III by Shenoy et al [21]. Our observed changes in the activation energy are consistent with the results obtained for the T 1 of 1 H by Watton et al [13] and Shenoy et al [21].…”

“…The trend observed for T 1 below 133 K is similar to that reported for phase III by Shenoy et al [21]. Our observed changes in the activation energy are consistent with the results obtained for the T 1 of 1 H by Watton et al [13] and Shenoy et al [21]. At temperatures below 27 K, the activation energy has a value smaller than 12.39 cal mol −1 .…”

“…In phase III , the variation of T 1 with temperature exhibits a maximum; T 1 slowly increases as the temperature is increased and then begins to decrease after passing through a maximum. This trend is similar to that reported by Shenoy et al [21]. Then, in phases III and IV, T 1 undergoes fast motions, whereas in phase III the motion is much slower.…”