Ammonium ion diffusion in (NH4)3H(SO4)2 was studied by means of 1H spinlattice

relaxation times in the rotating frame, T1ρ. The 1H T1ρ values were measured

at 200.13MHz in the ranges of 380 to 490K. The ammonium protons and the acidic

protons have independent T1ρ values, suggesting that the spin diffusion between the

two species was ineffective. The translational diffusion of the ammonium ions was

the most dominant mechanism to relax both the ammonium protons and the acidic

protons in phase I. The 1H T1ρ values in phase I were analyzed theoretically and the

motional parameters were obtained. The activation energy (Ea) was 75kJ/mol and

the mean residence time at the infinite temperature (τ0) was 4.0 x 10−15s. This

motion was three or four orders of magnitude slower than that of the acidic

protons.

Ammonium Ion Diffusion in the Superprotonic Phase of (NH4)3H(SO4)2 as Studied

by 1H Spin-Lattice Relaxation Times in the Rotating Frame. H.Omi, K.Suzuki,

S.Hayashi: Solid State Ionics, 2008, 178[35-36], 1792-7