Excited state charge distribution

While the difference in the upwards and downwards solvent responses presented in Figure 3 is striking, this is not the first time that variations in solvation dynamics for the same solvent have been observed. Experimental studies have shown differences in solvation response for different probe molecules in the same solvent. This is a direct indication that probe molecules which have different excited state charge distributions and different mechanical interactions with the solvent produce differing relaxation dynamics. Computer simulations have also observed differing solvation dynamics for the forward and reverse transitions of the sudden appearance of charge, indicative of a solute-dependent solvent response. Moreover, theoretical work has shown that dielectric solvation dynamics is sensitive to the shape of a solute, and that solute size is intimately connected to viscoelastic relaxation. It is these effects which are manifest in the... 

The above trends of the ground and excited state charge distributions obtained by calculations A and B indicate that i) So- S, transition brings about a dipole moment increase, the size of which decreases with an increase in solvent polarity, and ii) at all fc( )>0 the dipole moment increase predicted by calculation B is smaller than that found by calculation A. This is clearly... 

The most intriguing aspect of the emission response is the blue shift that occurs upon the transition from fluid to rigid media, as in the transformation of a sol to a xerogel (115, 136-140). Formerly attributed to rigidochromism this phenomenon is actually a result of inhibition of solvent reordering around the dipole, which is created by an asymmetric excited-state charge distribution (136, 140). The solvent molecules that reorient themselves around the dipole lower... 

Davidson s (Appendix E) algorithms. A two-dimensional real space representation of the resulting transition density matrices is convenient for an analysis and visualization of each electronic transition and the molecular optical response in terms of excited-state charge distribution and motions of electrons and holes (Section IIC). Finally, the computed vertical excitation energies and transition densities may be used to calculate molecular spectroscopic observables such as transition dipoles, oscillator strengths, linear absorption, and static and frequency-dependent nonlinear response (Appendix F). The overall scaling of these computations does not exceed X in time and in memory (A being the... 

Excited State Charge Transfer. Our goal here is to discuss aspects of ET theory that are most relevant to the charge transfer processes of excited molecules. One important point is that often the solvent relaxation is not well modeled with a single t, but rather a distribution of times apply. This subject has been treated by Hynes [63], Nadler and Marcus [65], Rips and Jortner [66], Mukamel [67], Newton and Friedman [68], Zusman [62], Warshel [71], and Fonseca [139], We also would like to study ET in the strongly adiabatic regime since experimental results on BA indicate this is the correct limit. Finally, we would like to treat the special case of three-well ET, which is the case for BA. 

Figure 27. The time-dependent probability distribution function p(z, f) for the excited state charge transfer of BA from a GLE simulation (See Refs. 132 and 133). The 5, potential employed in the simulation is shown in Figure 24.

Figure 4.31 Reorganization of the charge distribution in benzyl anion upon HOMO —> LUMO excitation. The charge distribution in the ground state is given by the square of the HOMO and that of the excited state by the square of the LUMO...

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