Solute Dependence of Three Pulse Photon Echo Peak Shift Measurements in Methanol Solution

Abstract

Three pulse photon echo peak shift (3PEPS) measurement has recently become a popular method to study solvation and protein dynamics. In this paper, dependence of the 3PEPS signal on probe solute molecules was studied using several xanthene dyes and styryl dye molecules in methanol and compared with pumpprobe measurements. For xanthene dyes, the decay was faster when the blue side of the absorption spectrum was excited. This effect is considered to be the result of a limited observation window and vibrational relaxation of the excess energy through higher density of states in the excited state. Nonlinear coupling may be also need to be considered. It seemed that the 3PEPS signal was more sensitive to excited state dynamics rather than to the ground state ones. For styryl dyes, a gradual increase of the peak shift was observed in the picosecond region, which may be the result of photoinduced isomerization.

Hybrid molecular dynamics‐quantum mechanics simulations of solute spectral properties in the condensed phase: Evaluation of simulation parameters

“…However, as mentioned earlier, experiments have shown that solvent motions ∼10 ps, as well as a static component (i.e. ≫100 ps), are needed to fully describe solvation dynamics in methanol 31. We have evaluated trajectory length dependence for all of the model chemistries out to 25 ps, for CIS/STO‐3G out to 100 ps, and for ZINDO/s out to 300 ps.…”

“…Experiments have suggested long‐timescale dynamics of 8.4 ± 1.6 ps for Ox4 in methanol as well as a significant static (≫ 100 ps) component 31. Thus, as with any discrete solvation model, achieving a truly ergodic ensemble of configurations is extremely challenging.…”

“…The optical response functions for 3PEPS have been described elsewhere15, 30 in detail, and are not presented here. Note that the only information needed for calculation of a 3PEPS decay is the line‐broadening function and parameters describing the experimental conditions, such as the pulse‐width, which have been taken from Nagasawa et al,31, who generously shared their experimental 3PEPS data.…”

Ultrafast Excited-State Isomerization Dynamics of 1,1‘-Diethyl-2,2‘-Cyanine Studied by Four-Wave Mixing Spectroscopy

“…11,29,30 As pathways resulting from ESA enter the total response function with a negative signsopposite to ground-state absorption and stimulated emission pathways, which are associated with a positive sign 17 s interference between different contributions can lead to increasing TG and three-pulse photon-echo signals. 11,[29][30][31]58 The double-sided Feynman diagrams that contribute to the excitedstate isomerization signal of 1122C are schematically presented in Figure 2. Diagrams (i) and (ii) are identical to those expected for a simple two-level system.…”

Two-Dimensional Analysis of Integrated Three-Pulse Photon Echo Signals of Nile Blue Doped in PMMA

“…It is also known that the echo peak shift depends on excitation wavelength. 25,26,58 To extract all of the information embraced in the signal, the echo intensity should be carefully monitored as a two-dimensional function of τ and T. Here we report two-dimensional measurements of the integrated three pulse photon echo signal by controlling the first and the second time periods, τ and T, and integrating the echo signal over the third period, τ′. The sample we have measured is a Nile blue doped poly(methyl methacrylate) (NB/PMMA) film.…”