Non-equilibrium effects in ultrafast photoinduced charge transfer kinetics

How can infra-red excitation both accelerate and slow charge transfer in the same molecule?

“…The difference between the equilibrium and non-equilibrium ET rates may also be described in the language of effective activation free energies (see ESI Section III.4 † for detail). 37 – 39 For example, a general formulation of transition state rate theory was used to show that, far from equilibrium, the non-equilibrium rate can be described with a product of an exponential activation factor and a pre-factor. 37 The exponential factor is associated with an effective reaction barrier.…”

Structural dynamics of an excited donor–acceptor complex from ultrafast polarized infrared spectroscopy, molecular dynamics simulations, and quantum chemical calculations

“…[3][4][5][6] In this respect, significant advances in our understanding of electrontransfer processes have been achieved thanks to studies of DACs, including the role of intramolecular modes [7][8][9] and the effect of non-equilibrium dynamics. [10][11][12] Surprisingly, little is known about the structure of DACs in liquids, although such information is crucial for a quantitative analysis of their electron-transfer dynamics. DACs are often assumed to have a well-defined structure consisting of D and A moieties in a p-stacked face-to-face arrangement.…”

Effect of Vibrational Transitions on the Nonthermal Charge Transfer Probability

“…One of the reasons is the large number of regimes in which ET can proceed and as well as the variety of energical parameters controlling this process. In different regimes, the ET rate constant dependencies on the controlling parameters can vary greatly, and in some regimes they may even be opposite [4]. It creates difficulties in controlling ET in real molecular systems.…”