Abstract
(17)O NMR methods are emerging as a powerful tool for determination of structure and dynamics in materials and biological solids. We present experimental and theoretical frameworks for measurements of (17)O NMR relaxation times in static solids focusing on the excitation of the central transition of the (17)O spin 5/2 system. We employ (17)O-enriched NaNO(3) as a model compound, in which the nitrate oxygen atoms undergo 3-fold jumps. Rotating frame (T(1ρ)), transverse (T(2)) and longitudinal (T(1)) relaxation times as well as line shapes were measured for the central transition in the 280 to 195 K temperature range at 14.1 and 18.8 T field strengths. We conduct experimental and theoretical comparison between different relaxation methods and demonstrate the advantage of combining data from multiple relaxation time and line shape measurements to obtain a more accurate determination of the dynamics as compared to either of the techniques alone. The computational framework for relaxation of spin 5/2 nuclei is developed using the numerical integration of the Liouville - von Neumann equation.