text: The dipolar powder pattern (also Pake pattern) has a very characteristic shape that arises when two nuclear spins are coupled together within a crystallite. The splitting between the maxima (the "horns") of the pattern is equal to the dipolar coupling constant .:
  where γ and γ are the gyromagnetic ratios of the dipolar-coupled nuclei,  is the internuclear distance,  is the reduced Planck's constant, and  is the vacuum permeability.