Comparison of spin–lattice relaxation measurements made in the presence of strong radiation damping

The scientific literature contains reports of external magnetic fields affecting the fundamental properties and structure of water, including a report of the rotational motion of water molecules being slowed due to increased hydrogen bonding resulting from magnetic treatment. To investigate such a change in molecular motion, 1H spin–lattice relaxation times of water were measured at increasing magnetic field strengths. Strong radiation damping was observed at each magnetic field strength when using inversion-recovery experiments. To measure the relaxation times in the presence of radiation damping, several experimental methods of saturation recovery to measure spin–lattice relaxation were applied to a 90% H2O sample to obtain results as a function of field strength for proton frequencies from 300 to 800 MHz.