The diffusion coefficients were measured using a 400 MHz
Bruker AVANCE II NMR spectrometer. The NMR pulse sequence
used was a complex bipolar stimulated echo pulse field gradient
(BPStE-PFG) originally designed by Cotts [35]. The Cotts sequence is
an adapted from the Stejskal-Tanner pulse sequence [36] which
eliminates background magnetic fields. Background magnetic field
gradients manifest due to inhomogeneities in the magnetic field.
This produces cross terms of the applied magnetic gradients and
the background magnetic gradients. This introduces the relation for
intensity of signal in the form of Eq. (1).