Nuclear magnetic resonance magnetic dipolar spectral density functions for two-dimensional lattice diffusion: hexagonal systems

摘要

Previous calculations of spectral density functions for like-spin magnetic dipolar interactions between spins undergoing two-dimensional diffusion are extended to the hexagonal lattice and the honeycomb structure. The diffusion models used are the random-walk and mean-field models. Analytic approximations to the functions are obtained. It is shown that the simple function proposed by Richards cannot provide good accuracy over the whole range of frequency and temperature, and a modified function is suggested. [References: 11]