This is the model for 2-site exchange on most times scales (with the constraint that pA > pB), named after Carver and Richards (1972). It is selected by setting the model to `CR72'. It is the same as the full CR72 model described above, but with the simplification that R2A0 = R2B0. This simplifies the equations to
|R2eff = R20 + - νCPMGcosh-1D+cosh(η+) - D-cos(η-),||(11.27)|
where D± and η± are unchanged and
|Ψ||= kex2 - Δω2,||(11.28)|
|ζ||= - 2Δω(pAkex - pBkex).||(11.29)|
As mentioned in the `CR72 full' model section, this model is not accurate when the motional process is very slow. In that case please use the `TSMFK01' model in Section 11.3.6 on page instead.
More information about the CR72 model is available from:
The relax user manual (PDF), created 2019-06-14.