The magic angle is a precisely defined angle, the value is approximately 54.7°. Hence, two nuclei with a dipolar
coupling vector at an angle of approximately 54.7° to a strong external
magnetic field have zero dipolar
coupling.
Magic angle spinning is a technique in solid-state
NMR spectroscopy, which employs this principle to remove or reduce dipolar couplings, thereby increasing spectral
resolution.
In
MRI, the magic angle effect visualizes as bright spots through an increased
T2 time on short
echo time (TE) images, for e.g. collagen fibers of tendons and ligaments, which are oriented at the magic angle of approximately 54.7° to the
magnetic field.