Molecular simulation of solvent-induced stokes shift in absorption/emission spectra of organic chromophores.
The values of steady-state solvatochromic Stokes shifts (SS) in absorption/emission electronic spectra of organic chromophores are studied theoretically in the framework of the Hush-Marcus model. Charge distributions for chromophore solutes in their S0 and S1 states are found by means of conventional quantum-chemical methods combined with the continuum PCM approach for treating solvation effects. The solvent reorganization energies, which are expected to correlate with the solvent-induced part of 1/2 SS, are found in a molecular dynamics (MD) simulation which invokes a novel method for separation of the inertial piece of the electrostatic response (Vener, et al. J. Phys. Chem. B 2006, 110, 14950). Computations, performed in two solvents (acetonitrile and benzene), consider three organic dyes: coumarin 153 as a benchmark system and two other chromophores, for which experimental spectra are also reported. The results are found to be in reasonable agreement with the experiment. A consistent treatment of nonlinear effect in the solvent response, promoted by the polarizability of solutes and contributing to the solvent reorganization energies (Ingrosso, et al. J. Phys. Chem. B 2005, 109, 3553), improves the results of computations.
Nikitina
Ekaterina A
EA
Photochemistry Center, Russian Academy of Sciences, Moscow, Russia. ekaterina_nikitina@rambler.ru
Odinokov
Alexey V
AV
Grigoriev
Fedor V
FV
Basilevsky
Mikhail V
MV
Khlebunov
Artem A
AA
Sazhnikov
Vyacheslav A
VA
Alfimov
Mikhail V
MV