Electron jump, time-dependence

In a final step, the electron jumps in a very fast process directly to the emitter molecule and it results an excited emitter. This process may occur as singlet or triplet path (S-path, T-path) depending on the initial spin orientation of the electron-hole pair. The corresponding time constants are of the order of one picosecond (see next section). The population of Sn and Tn states, as shown in Fig. 3, is only depicted as an example. Subsequently, the system will exhibit the usual behavior of an optically excited emitter mole-... 

The time-dependence of an electron jump from an atom to an approaching nucleus is beyond the scope of this book. 

Additional deviations from the Nernst law [Eq. (4)] can come from kinetic effects in other words, if the potential scan is too fast to allow the system to reach thermal equilibrium. Two cases should be mentioned (1) ion transport limitation, and (2) electron transfer limitation. In case 1 the redox reaction is limited because the ions do not diffuse across the film fast enough to compensate for the charge at the rate of the electron transfers. This case is characterized by a square-root dependence of the current peak intensity versus scan rate Ik um instead of lk u. Since the time needed to cross the film, tCT, decreases as the square of the film thickness tCT d2, the transport limitation is avoided in thin films (typically, d < 1 xm for u < 100 mV/s). The limitation by the electron transfer kinetics (case 2) is more intrinsic to the polymer properties. It originates from the fact that the redox reaction is not instantaneous in particular, due to the fact that the electron transfer implies a jump over a potential barrier. If the scan... 

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