This is the original Luz and Meiboom 1963 relaxation dispersion model for 2-site fast exchange for SQ CPMG-type data. This model is labelled as LM63 in elax.
Parameters
The LM63 model has the parameters {$R_2^0$, $...$, $\Phi_{ex}$, $k_{ex}$}.
Reference
The reference for the LM63 model is:
- Luz, Z. and Meiboom, S. (1963). Nuclear magnetic resonance study of protolysis of trimethylammonium ion in aqueous solution - order of reaction with respect to solvent. J. Chem. Phys., 39(2), 366-370. (10.1063/1.1734254).
Links
The implementation of the LM63 model in relax can be seen in the: