Insights into the spin dynamics of a large anisotropy spin subjected to long-pulse irradiation under a modified REDOR experiment

Broadband excitation in solid-state NMR using interleaved DANTE pulse trains with N pulses per rotor period

“…Therefore, a portion of the magnetization dephased by anisotropic interactions cannot be refocused at the end of the rotor period and hence does not contribute to the powder magnetization. It has already been reported that a long rf pulse can scramble the magnetization of the different crystallites from powder samples when the nuclei are subject to large anisotropic interactions [40][41][42][43]. This scrambling results in an apparent saturation of the magnetization of a powder sample.…”

“…This scrambling results in an apparent saturation of the magnetization of a powder sample. This phenomenon has been used for hetero-nuclear distance measurement [40][41][42][43][44][45][46]. Fig.…”

Distance Measurements to Metal Ions and Other Quadrupolar Spins by Magic Angle Spinning Solid State NMR

“…This experiment is, therefore, highly robust, easy to apply, and efficient for long distances. A detailed analysis of this experiment81 shows that, indeed, there are many conditions in which the LA‐REDOR fraction can be modeled by either the universal REAPDOR curve or, similarly, by Eq. 7 with the Bessel terms given by ${J_{ \pm 1/4} \left( {\sqrt 2 \lambda } \right)}$ .…”

An optimal double-magic flip angle for performing the distance measurement REDOR experiment on a spin S=1

“…Assuming ideal pulses on the half-spin I, a general solution for the signal of a particular crystallite in the powder can be written as follows [15,16]: where ߥ (in Hz) is the dipolar frequency given by −ߤ (4ߨ) ିଵ ߛ ூ ߛ ௌ ℏ‫ݎ‬ ିଷ (γ is the gyromagnetic ratio, r is the internuclear distance, µ 0 is the vacuum permeability constant, ℏ is Planck's constant); ܵ క (ߙ, ߚ, ߛ; ‫)ݐ‬ represents the dipolar-dephased signal of a crystallite with a particular orientation represented by the three Euler angles α, β, γ and ݈ (ߙ, ߚ, ߛ) represents the probability for making a transition during the S-spin pulse between energy levels separated by a coherence order m for some crystallite. For the powder signal we get…”