These are materials where the relaxation rate is at much lower frequencies.
In Nuclear magnetic resonance the introduction of the paramagnetic group increases the relaxation rate of nearby nuclei.
Each scattering mechanism can be characterised by a relaxation rate 1/ which is the inverse of the corresponding relaxation time.
Then, the spectral width of the emitted photons is determined by the relaxation rate.
Protons in different tissues return to their equilibrium state at different relaxation rates.
The easiest approach is to replace the collision term by a phenomenological relaxation rate (-approximation).
The sum of the two rates is the observed relaxation rate.
The volume of the dilution is adjusted to obtain the relaxation rate at a specific denaturant concentration.
When the logarithm of these relaxation rates are plotted as a function of the final denaturant concentration, a chevron plot results.
The relaxation rate depends strongly on the mobility (fluctuations, diffusion) of the microscopic environment and the strength of the applied magnetic field.
