FIGURE 6.

The diffusion-in-a-cone model as applicable to lateral diffusion measurements in magnetically aligned bilayers using STE PFG NMR measurements. Collective fluctuations of the bilayer normal d modulate the angle θ so that the ensemble- and time-average of 〈sin²θ〉 enters Eq. 6. The normal is considered to diffuse freely in a cone of half-angle β₀, with its instantaneous orientation defined in terms of the polar-angle β and the azimuthal-angle α.