The effect of ionic diffusion upon Li spin-lattice relaxation in Li2Si4O9 glass was studied at 2000 to 3800K. The orientational pair correlation function, G(t), associated with spin-lattice relaxation was deduced, for individual Li ions, from the trajectories of the constituent ions at various temperatures. The temporal decay of G(t) was found to be non-exponential and could be described by the stretched-exponential functional form, exp(-t/τSLR)β. It was shown that the non-exponential behavior of G(t) was intrinsic to the system and possibly originated from hierarchically constrained relaxation processes. The activation energies associated with Li diffusion, τSLR, and the average conductivity relaxation time <τσ> were shown to be in excellent agreement; indicating that the same microscopic dynamic processes were responsible for spin-lattice relaxation, diffusion and conductivity. However, τSLR was found to be nearly an order of magnitude longer than <τσ> over the entire temperature range of the simulations. This reflected the fundamental differences between the correlation functions associated with spin-lattice relaxation and conductivity relaxation.

A Molecular Dynamics Simulation Study of Ionic Diffusion and NMR Spin-Lattice Relaxation in Li2Si4O9 Glass. Sen, S., Mukerji, T.: Journal of Non-Crystalline Solids, 2001, 293-295[1], 268-78