For this model, the equations from Korzhnev05 have been used.
The $\mathrm{R}_{1\rho}$ value for state A magnetisation is defined as
\begin{equation}
    \mathrm{R}_{1\rho} = - \frac{1}{T_\textrm{relax}}  \cdot \ln \left( M_0^T \cdot e^{R \cdot T_\textrm{relax}} \cdot M_0 \right),
\end{equation}
 
For this model, the equations from \citet{Korzhnev05a} have been used.
The $\mathrm{R}_{1\rho}$ value for state A magnetisation is defined as
\begin{equation}
\begin{align}
    M_0    &= \begin{pmatrix} \sin{\theta} \\ 0 \\ \cos{\theta} \\ 0 \\ 0 \\ 0  \end{pmatrix}, \\
    \theta &= \arctan \left( \frac{\omegaoneomega_1}{\offsetAOmega_\textrm{A}} \right).
\end{align}
    R = \begin{pmatrix}
          -\mathrm{R}_{1\rho}prime-\kAB & -\delta_A           & 0           & \kBA                & 0                   & 0 \\
          \delta_A            & -\mathrm{R}_{1\rho}prime-\kAB & -\omegaone omega_1  & 0                   & \kBA                & 0 \\          0                   & \omegaone omega_1           & -\Rone-\kAB & 0                   & 0                   & \kBA \\
          \kAB                & 0                   & 0           & -\mathrm{R}_{1\rho}prime-\kBA & -\delta_B           & 0 \\
          0                   & \kAB                & 0           & \delta_B            & -\mathrm{R}_{1\rho}prime-\kBA & -\omegaone omega_1 \\          0                   & 0                   & \kAB        & 0                   & \omegaone omega_1           & -\Rone-\kBA \\
        \end{pmatrix},
\end{equation}