Dynamic-Angle Spinning of Quadrupolar Nuclei
نویسنده
چکیده
In dynamic-angle spinning (DAS), a sample spins around an axis inclined at an angle ti( t) with respect to the magnetic field such that the averages of P,(cos 6’) are zero. The simplest case is where (I(t) assumes two discrete values 8, and & (complementary DAS angles) such that the averages of PZ( cos 8) and P4( cos 0) are zero, thereby removing second-order quadrupolar (and dipolar) broadening. Examples of DAS complementary angles are 8, = 37.38” and fIZ = 79.19”. Experimental details for DAS experiments are provided and applications to sodium-23 and oxygen-17 NMR illustrate the enhanced resolution achieved by removing the second-order broadening inherent in magic-angle spinning.
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