Fig. 3. Diffusional and nanoconfined dynamics in in PTI·H₂O.

(A) Γ_T versus Q² plot showing evidence for c-o-m diffusional displacements of H₂O molecules from QENS data above 255 K. A small Q dependence is also apparent in IN16B data at 245 K. Γ_T (square symbols) is obtained as the half-height linewidth of the narrow Lorentzian component. (B) Detail of Γ_T(Q²) for 245 to 275 K experiments showing the initial Q-independent signature of nanoconfined H₂O dynamics. (C) Temperature behavior of the Q-independent Γ_R contribution to the broad Lorentzian component in Fig. 2 (A and B). (D) EISF data obtained at OSIRIS and modeled by assuming rotation of intercalated water molecules nanoconfined within a spherical volume with radius a. The data were fit using 2a = 6, 7, and 9 Å at 255, 265, and 275 K, respectively (inset). A similar range of values was also estimated independently from fitting the plateau in the low-Q Γ_T (Q²) data (Fig. 3A). The EISF for PTI·H₂O above 300 K was modeled assuming free rotation of H₂O molecules within a sphere of radius 0.98 Å constrained by the O─H bond length.