Calculation of the NMR second moment for solid benzene with rotation and diffusion of molecules - Numerical approach

Numerical calculations of the NMR second moment in case of rotation and diffusion of molecules were performed. As an example computer simulations oi molecular reorientation and self-diffusion in solid benzene have been performed. For each model and rate of motion the Van Vleck's second moment of the proton NMR absorption spectrum was calculated, and these values were compared with experimental data. It is concluded that restricted self-diffusion must be implied in order to obtain better agreement between calculated and experimental NMR second moments. The temperature at which self-diffusion was detected through NMR line-width narrowing was found to be about 120 K, nearly 80 K less than the temperature at which the self-diffusion was detected by T-1 rho relaxation measurements.