Fig. 3.

Structural evolution during LLT at various $T_{\text{a}}$ s. (A) Time evolution of $I\left(q\right)$ in a small-angle regime during LLT at $T_{\text{a}}$=218 K. The data are vertically shifted for clarity. The blue filled circles show $I\left(q\right)$ of liquid II at 241 min. The contribution from the wide-angle scattering is subtracted from the data as in Fig. 1A. The red solid curves represent the best fit of the relation $I\left(q\right)=I_{\text{LFS}}\left(q\right)+I_S\left(q\right)+I_{\text{MC}}\left(q\right)$ with Eqs. 6 and 7. The shoulder around 1 ${\text{nm}}^{-1}$ is the scattering contribution from LFS. The scattering signal in the light blue region is mainly from long-range density fluctuations associated with LLT in the early stage, and from microcrystallites in the late stage. (B) Time evolutions of the normalized $I_{\text{LFS}}\left(0\right)$ and ${\varphi }_{\text{MC}}$ for various $T_{\text{a}}$ s. For 212, 213, and 214 K, we used an equation describing SD-type ordering as the fitting function (20). For 216 and 218 K, where NG-type LLT proceeds, we used a Kolmogolov–Avrami equation to describe the evolution (20). The solid curves indicate the best fit to $I_{\text{LFS}}\left(0\right)$ whereas the dash–dot curves correspond to ${\varphi }_{\text{MC}}$. (C) $T_{\text{a}}$ dependence of the delay time, $\mathrm{\Delta }\tau ={\tau }_{\text{MC}}-{\tau }_{\text{LFS}}$. See text for the definition of ${\tau }_{\text{LFS}}$ and ${\tau }_{\text{MC}}$. (D) $T_{\text{a}}$ dependence of the temporal change of $D_{\text{c}}$. Each arrow indicates the onset of the change in $D_{\text{c}}$, i.e., the onset of microcrystal formation. (Inset) Relation between the onset time of ${\varphi }_{\text{MC}}$, $t_{\text{MC}}$, and that of $D_{\text{c}}$, $t_{\text{D}}$, indicating the relation $t_{\text{MC}}\sim t_{\text{D}}$.