Relative population of donor state vs time (in vibrational periods) after electronic excitation from vibrational ground state (solid black curve) and from impulsively displaced vibrational wave packet (solid gray curve). Corresponding dashed curves are semi-analytical predictions of weak EET-coupling theory derived in the Appendix, which depend only on vibronic state populations and miss effects due to vibrational coherence.
Pump-probe signal (black curve, left ordinate in units of ) and pump-probe difference signal (gray curve, right ordinate in units of ) as a function of delay time between pump and probe pulses. Signals are calculated for an isotropic sample of the model energy-transfer complex with equal-energy monomers having perpendicular transition moments.
Stimulated-emission contributions to the pump-probe and pump-probe difference signals shown in Fig. 2 from those wave-packet overlaps that would take nonzero values if one monomer’s transition moment were oriented vertically (parallel to the control-pulse polarization) and the other’s were oriented horizontally (parallel to the pump and probe polarization).
Upper panel: average signals from a collection of 1000 model-system dimers (, ), whose site energies are chosen from independent normal distributions with FWHM equal to the vibrational frequency. Pulse parameters are the same as in Fig. 2, except the temporal widths of the pump and probe pulses are and , respectively. Pump-probe signals are shown for HH and HV polarizations; pump-probe difference signals for VHH and VHV polarizations. Lower panel: signal anisotropies for the inhomogeneously broadened model system, in black for pump-probe and gray for pump-probe difference.
Pump-probe signal (black curve, left ordinate) and pump-probe difference signal (gray curve, right ordinate) as function of the delay between pump and probe pulses. Upper panel shows pump-probe and pump-probe difference signals from simplified model of DTA treating only the dynamics of the low-frequency mode-12. Lower panel plots stimulated-emission contributions from DTA-12.
Donor-excited-state population dynamics for DTA-12 without (solid black curve) and with (solid gray curve) prior impulsive excitation of mode-12 vibration in acceptor chromophore. Transition-dipole moment of acceptor chromophore is aligned with vertical control-pulse polarization. Transition-dipole moment of donor is aligned with horizontal pump-pulse polarization. Dashed curves show corresponding predictions of weak EET-coupling approximation (see Appendix A).
Anisotropies calculated from inhomogeneously broadened stimulated-emission component of the pump-probe signal (black) and pump-probe difference signal (gray).
Donor-state survival probabilities for oriented downhill EET model without (solid black curve) and with (solid gray curve) prior impulsive excitation of acceptor-mode vibration. Coherent vibrational excitation of acceptor is seen to accelerate short-time EET in this system. Dashed curves give the corresponding predictions under weak EET-coupling approximation.
Pump-probe signal (black curve) and pump-probe difference signal (gray curve) for isotropic sample of downhill EET dimer using VHH polarization scheme and probe-pulse center frequency which select primarily for nuclear probability density in the donor-excited state.
Contributions from stimulated-emission (top panel), excited-state absorption (middle), and ground-state bleach (bottom) to pump-probe (black curves) and pump-probe difference (gray curves) to signals shown in Fig. 9.
Same as Fig. 9, but with VHV polarization and probe-pulse center frequency selecting for nuclear probability density in the acceptor-excited state.
Illustration of possible vibrational-control strategy for the DTA-12 model with its weak electronic-vibrational coupling. Upper panel shows spatially translated vibrational wave function at instant of transfer to donor-excited state. Lower panel compares subsequent donor-state survival probability (gray dashed line) to that following direct excitation from vibrational ground state (solid black line).
Symmetric and antisymmetric vibrational coordinates plotted on donor and acceptor coordinate axes. The lowest-energy vibrational state in the donor-excited (acceptor-excited) electronic state is centered at . Also shown are the location (at the origin) of the lowest vibrational state in the electronic ground state and the location of a ground-state wave packet displaced by along the axis.
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