Figure 9.

EA of the FRET signal from the slow-rotating fluorophore pair as a function of the distance between fluorophores. The EA for each distance was calculated by numeric averaging of $\frac{2}{5}{P}_2\left(\cos {\beta }_{\text{da}}\right)$ from Eq. 18 over anisotropic angular distribution with the extra weight equal to the FRET efficiency, and normalized by the average FRET efficiency, calculated as described in the legend for Fig. 8. The numeric result is not very precise due to the high dimension of integration. The EA increases with the distance to the finite limit ∼0.016.