Theory of fluorescence spectrum dynamics and its application to determining the relaxation characteristics of the solvent and intramolecular vibrations

Effect of Symmetry Breaking in Excited Quadrupole Molecules on Transition Dipole Moment

“…Fluctuations in μ eg affect the absorption and fluorescence spectra, which makes it possible to detect manifestations of the fluctuations experimentally. To describe the effect of fluctuations we use eqs and to calculate the absorption and stationary fluorescence spectra − where A ge (ω) and I eg (ω) are absorption and fluorescence spectra, respectively; G e ( D m ) = min D G is free energy of the excited state obtained in the adiabatic approximation by minimizing the functional eq with respect to D (see Figure ); G g ( D m ) = λ or D m 2 /2 + ΔG is the free energy of the ground state (here we assume that the dipole moment of the dye in the ground state is zero, and the interaction between the dye and the polar solvent is negligible); ΔG is the free energy change between the first excited and ground states at zero polarization of the solvent, D m = 0; the Dirac δ-function reflects the energy conservation law; ℏ is the Planck constant; S is the Huang–Rhys factor; and ρ g ( D m ) and ρ e ( D m ) are the equilibrium population distributions in the ground and excited states, respectively. They are given as Z g and Z e are the normalization factors and G e is given by eq , k B is the Boltzmann constant, and T is the temperature.…”

“…The model with one vibrational mode, eq , can be easily generalized to account for the reorganization of many intramolecular high-frequency vibrations, but this does not affect the results obtained in this work. Equations and are obtained within the Golden Rule approximation. − …”

Data analysis in transient electronic spectroscopy – an experimentalist's view

“…[46,49] Kumpulainen et al recently showed it to be in good agreement with the time-zero emission spectra extracted using broadband fluorescence up-conversion techniques. [60] As noted above however, the recent extension of the DHO model by Fedunov et al [56] was able to circumvent the need for this estimation.…”

“…Recently, the formalism has been further extended by Fedunov et al to explicitly include vibrational relaxation processes in the electronic excited state, as well as explicitly connecting the relaxation dynamics of the fluorescence spectrum to an arbitrary solvent relaxation function. [56] In addition, and significantly, they were also able to circumvent the long-standing problem [21] of the estimation of the fluorescence spectrum pre-solvation (discussed in Section ??) by using information about the pump pulse used for excitation of the fluorophore to calculate the build-up dynamics of the excited-state wavepacket.…”

“…by using information about the pump pulse used for excitation of the fluorophore to calculate the build-up dynamics of the excited-state wavepacket. [56] University of Geneva 21…”