Figure 1

(a) Adiabatic potential curves of the electronic excited and ground states of a dye molecule in a reverse micellar solution as a function of a configuration coordinate. Change in the potential curves on water shedding from the reverse micelle is schematically shown by red curves. (b) Schematic cross-section diagrams of the dye-molecule-containing reverse micelle before (left) and after the water shedding with the dye molecule (right).Reuse & Permissions

Figure 2

Schematic diagram of the temperature dependence of the spectral width parameter σ for the dye-molecule-containing water droplet. Below $T_{\mathrm{C}}$, the droplet excluded from the reverse micelle is not constrained by the reverse micelle and its water molecules attain diffusionlike motion.Reuse & Permissions

Figure 3

Temperature dependence of σ in the reverse micellar solution at $w_0$ = 2, 3, and 5, shown by symbols. Solid lines show the results due to linear curve fitting [α$T$ +β; α: slope (cm${}^{-2}$ K${}^{-1}$); $T$: temperature; β: $Y$ intercept (10${}^5$ cm${}^{-2}$)] of the data. The parameter values obtained by the fitting are as follows. Temperature range I: $w_0$ = 2 (α = 290, β = 3.19), $w_0$ = 3 (α = 540, β = 2.42), $w_0$ = 5 (α = 640, β = 1.8); range II: $w_0$ = 2 (α = 1710, β = 0), $w_0$ = 3 (α = 1530, β = 0), $w_0$ = 5 (α = 1380, β = 0); range III: $w_0$ = 2 (α = 890, β = 1.71), $w_0$ = 3 (α = 820, β = 1.44). FWHM is the full width at half maximum, which is derived from $2\sqrt{\sigma \ln 2}$.Reuse & Permissions

Figure 4

The spectra calculated from Eq. (A1) at (a) 300 K and (b) 150 K. The parameter values are as follows: $A_1$ = 1, $E_1$ = 18 750 cm${}^{-1}$, κ${}_1$ = 1300 cm${}^{-2}$ K${}^{-1}$, $A_2$ = 0.5, $E_2$ = 19 700 cm${}^{-1}$, κ${}_2$ = 1500 cm${}^{-2}$ K${}^{-1}$.Reuse & Permissions

Figure 5

Results of the Gaussian curve fitting using Eq. (1) of the absorption spectrum calculated from Eq. (A1) at (a) 300 K and (b) 150 K on the low-frequency side of the spectrum. The residual curves are also depicted. The absorption maximum is normalized to unity. We note that the frequency at the absorption maximum changes with temperature. Therefore, the upper limit ($R_U$) of the data range for the fitting is defined by the frequency difference from the absorption maximum; positive values of $R_U$ mean the position on the high-frequency side from the absorption maximum. The values of $R_U$ are 140 cm${}^{-1}$ (red), 0 cm${}^{-1}$ (green), $-$140 cm${}^{-1}$ (blue), $-$280 cm${}^{-1}$ (purple red), and −420 cm${}^{-1}$ (olive). The lower limit of the data range for the fitting is set at the frequency that leads to 0.1 of the absorption amplitude on the low-frequency side; this value, however, has no effect on the result of the fitting, because the tail of the absorption spectrum in the low-frequency region is Gaussian without the effects of the vibronic band. (c) and (d) Temperature dependences of $E$ and σ obtained by the fitting. The temperature dependence of σ at κ${}_1$ = 1300 cm${}^{-2}$ K${}^{-1}$ is shown by a solid line in (d). The value of $R_U$ decreases according to the direction of the arrows.Reuse & Permissions

Figure 6

Results of the Gaussian curve fitting using Eq. (1) with $E$ = 18 750 cm${}^{-1}$ of the absorption spectrum calculated from Eq. (A1) at (a) 300 K and (b) 150 K on the low-frequency side. The residual curves are also depicted. The absorption maximum is normalized to unity. The values of $R_U$ are 140 cm${}^{-1}$ (red), 0 cm${}^{-1}$ (green), −280 cm${}^{-1}$ (blue), and −420 cm${}^{-1}$ (olive). The lower limit is set at the frequency that leads to 0.1 of the absorption amplitude in the low-frequency region. (c) Temperature dependence of σ obtained by the fitting. The value of $R_U$ decreases according to the direction of the arrows.Reuse & Permissions

Figure 7

Results of the Gaussian curve fitting using Eq. (1) of the absorption spectra measured at (a) 297 K, (b) 210 K, and (c) 170 K. The residual curves are also depicted. The absorption maximum is normalized to unity. (d) Temperature dependence of $E$ obtained by the fitting. The value of $R_U$ decreases according to the direction of the arrows except for $R_U=-280{\mathrm{cm}}^{-1}$. The Gaussian curves at $R_U=-280{\mathrm{cm}}^{-1}$ almost coincide with those at $R_U=0{\mathrm{cm}}^{-1}$ in (a) and (c), whereas it has the largest amplitude in (b).Reuse & Permissions

Figure 8

Results of the Gaussian curve fitting using Eq. (1) with $E$ = 18 750 and 18 765 cm${}^{-1}$ of the absorption spectra measured at (a) 297 K, (b) 210 K, and (c) 170 K. The residual curves are also depicted. The absorption maximum is normalized to unity. (d) The temperature dependence of σ obtained by the fitting. The parameter values for solid lines [α$T$ +β; α: slope (cm${}^{-2}$K${}^{-1}$); $T$: temperature, β: $Y$ intercept (10${}^5$ cm${}^{-2}$)] are as follows. Temperature range I (red): $E$ = 18 750 cm${}^{-1}$ (α = 540, β = 2.4), $E$ = 18765 cm${}^{-1}$ (α = 470, β = 2.73); range II (blue): $E$ = 18 750 cm${}^{-1}$ (α = 1530, β = 0), $E$ = 18 765 cm${}^{-1}$ (α = 1590, β = 0); range III (green): $E$ = 18 750 cm${}^{-1}$ (α = 820, β = 1.44), $E$ = 18 765 cm${}^{-1}$ (α = 810, β = 1.58).Reuse & Permissions