INTERFACIAL AND CONFINED WATER Part 1 doc

[...]... point, diameter of fluids shows a critical anomaly, which may behave as ∼ τ 1 α [14 ] or ∼ τ 2β [15 ], or as superposition of two contributions [16 ], where α ≈ 0 .11 [12 ] Diameter of the coexistence curve of bulk water may be described by the following equation [11 ]: ρd = (ρl + ρv )/2 = ρc 1 + 1. 45τ 1 α − 0 .10 τ − 0.35τ 1. 5−α − 0 .13 τ 2−α − 1. 35τ 5.5 (3) Universal behavior of the order parameter as well as of... curve This is a transition between a “normal” water with a density of about 1 g/cm3 and low-density water phase, enriched with tetrahedrally ordered four-coordinated water Phase diagram of bulk water 13 T (K) ST2RF ST2 300 250 200 0.9 1. 0 1. 1 ␳ (g/cm3) 1. 2 0.9 1. 0 1. 1 1. 2 ␳ (g/cm3) Figure 7: Schematic locations of the liquid–liquid coexistence regions of model water (shadow areas) with respect to the liquid... homogeneous equilibrium water phase can exist, and all changes are continuous and smooth The coexistence pressure near the melting point is about 6 · 10 −3 of ambient pressure (1 bar), 1 2 Interfacial and confined water 600 500 400 T (K) experiment ST2RF ST2 TIP4P SPCE SPCE* TIP4P fit 300 200 10 0 0.0 0.2 0.4 0.6 0.8 1. 0 1. 2 ␳ (g/cm3) Figure 1: Experimental liquid–vapor coexistence curve of water [3] (thick... critical point and mark some specific 0.6 experiment 0.5 TIP4P water D␳ 5 (␳l 2 ␳v)/2 0.4 LJ fluid ␶␤ 0.3 0.2 0. 01 0 .1 ␶ 5 (Tc 2 T )/Tc Figure 3: A log–log plot of the order parameter Δρ vs reduced temperature τ for real water [3] (thick solid line), TIP4P water model [28], and for LJ fluids [29] Scaling equation (1) with β = 0.326 [12 ] is shown by straight dashed lines 6 Interfacial and confined water change... with pressure at high temperatures, and such behavior is observed in other (normal) fluids [3] However, anomalous increase of D, 1/ η, and 1/ τ2 upon pressurization was observed at temperatures below about 300 K [10 2 10 6] As a result, D, 1/ η, and 1/ τ2 pass through a maximum, and the residence time passes through a minimum at P ≈ 1 to 2 kbar The observed slowing down of water dynamics with approaching liquid–vapor... kbar), when T = 297 K; at ρ ≈ 1. 07 g/cm3 (P ≈ 2 .1 kbar), when T = 316 K; and at ρ ≈ 1. 04 g/cm3 (P ≈ 1. 9 kbar), when T = 353 K [10 8] Discontinuity in the pressure dependence is also seen in the Raman spectra of liquid water at ambient temperature, when ρ ≈ 1. 13 g/cm3 [10 9] Clearly, these anomalies cannot originate from the first (lowest density) liquid–liquid transition of water The thermodynamic points... prewetting critical point Surface transitions of water 19 Ising magnet, short-range surface field h1 Fluid, long-range fluid–wall interaction U0 1 prew e T/Tc tting 1 2nd-order drying 2nd-order wetting 2nd-order wetting (?) 1st-order wetting 1st-order wetting 0 2h1 C 1h1 U0 strengthening U0 Figure 8: Left panel: schematic surface phase diagram of the Ising model [11 3] showing the change of the wetting transition... [13 1] A sequential wetting, when the first-order wetting transition is followed by the critical wetting, was observed for pentane at water [13 2] and for hexane at salty water (brin) [13 3] More data on the experimental studies of the wetting transitions can be found in [13 4, 13 5] A drying transition of fluids, in fact, was never observed experimentally [13 6, 13 7] (see also Section 2.3 for studies of water) ... coexistence curve of ST2 water model [10 ] 10 Interfacial and confined water state and the fraction of these “solid particles” increases upon cooling This fraction is about 20% at boiling temperature, increases to about 30% at freezing temperature, and is 50 to 70% in “melting ice”, which we may consider a supercooled liquid water A solid particle represents a four-coordinated water molecule, which is the main... from ideal one and allows distinguishing of the tetrahedrally ordered water molecules [6, 10 , 44, 45] 8 Interfacial and confined water Temperature dependences of the fraction of water molecules with tetrahedral arrangement of the nearest four neighbors in liquid water calculated at the liquid–vapor coexistence curve for two water models are shown in Fig 5 There are less than 10 % of such water molecules . contributions [16 ], where α ≈ 0 .11 [12 ]. Diameter of the coexistence curve of bulk water may be described by the following equation [11 ]: ρ d = (ρ l + ρ v )/2 = ρ c  1 + 1. 45τ 1 α − 0 .10 τ − 0.35τ 1. 5−α −. 91 4.2 Phase transitions of confined water 98 4.3 Capillary condensation and capillary evaporation 11 4 5 Water layers at hydrophilic surfaces 12 1 5 .1 Percolation transition of hydration water 12 1 5.2.