Förster Energy Transfer Rates
As follows from the F\(o\)rster theory16, 17electronic couplings (\(V_{\text{DA}}\)) and spectral overlaps (\(J_{\text{DA}}\)) are used to calculate the resonance excitation energy transfer rate (\(k_{\text{DA}}\)):2, 6
\(k_{\text{DA}}=\frac{2\pi}{\hslash}{V_{\text{DA}}}^{2}J_{\text{DA}}\)(10)
The simplicity and convenience of this approach have made it a popular choice in cases where empirical emission and absorption spectra of donors and acceptors are available. Unfortunately, this expression does not provide details of the dynamics of coherent energy transfer. Therefore, quantum dynamics methodologies should be used instead. An example of application of the Förster approach is computation of EET rates in the photosensitizer m Tz-2I-BODIPY (Figure 2) that was proposed for conditional singlet oxygen generation in cells.4
In order to illustrate the effect of mutual donor-acceptor orientation change on the electronic coupling and EET rate, two geometries of the the photosensitizer are considered (Figure 3).