Oscillations, Waves, and Interactions - GWDG

394 U. Kaatze and R. Behrends
Figure 25. Relaxation rate Γ of concentration
fluctuations versus reduced
temperature ɛ for the nitroethane-3methylpentane
mixture of critical composition
[111]. The line in the graph of
the power law (Eq. (60)) with universal
exponent Z0˜ν = 3.065 [6] and with individual
amplitude Γ0 = 125·10 9 s −1 [111].
ξ0 = 0.37 nm as well as Γ0 = 6.4·10 9 s −1 , ethanol-dodecane [113]. The inset in Fig. 26
presents the scaled half-attenuation frequency which, when treated as an unknown
parameter, follows as
Ω BF
�
1
�
1/2 = Ω
0.414
F −1/2
BF
�
(Ω) − 1
�2 . (67)
The small scatter of the experimental data around the theoretically predicted value
2.1 emphasizes the appropriateness of the Bhattacharjee-Ferrell dynamic scaling
model.
Figure 26. Scaling function data according to Eq. (62): • [111], ◦ [121]. The full line is the
graph of the empirical Bhattarcharjee-Ferrell scaling function (Eq. (61) with x = BF). For
small Ω values the half-attenuation frequency data as calculated according to Eq. (67) are
displayed in the inset. The dashed line indicates the theoretically predicted Ω BF
1/2 = 2.1 [99].