Monitoring nuclear spin-flip processes and measuring spin-diffusion constants via hole burning into the magnetization

An NMR experiment is presented for measuring spin-diffusion coefficients and observing homonuclear spin-flip processes. The magnetization is erased or even inverted in a multitude of spatially confined regions containing only one or a few spins (‘hole burning’). During the following time evolution of these holes, the following three time regimes can be observed: (i) local spin dynamics, (ii) spin diffusion towards a uniform average magnetization, and (iii) longitudinal nuclear magnetic relaxation. The oscillating characteristic of magnetization exchange between neighboring protons is demonstrated on a liquid crystal.