Comparison of (a) the liquid-vapor coexistence curve, and (b) the surface tension of the BK water model with experimental data.35 Surface tension of the SPC/E and TIP4P models are also shown.36 The inset shows similar comparison of the saturated vapor pressure. Filled circles: data obtained from the simulations, solid curves: experimental data, open circles: estimated critical point of the model, asterisks: experimental critical point.
Number density profile of the BK water molecules along the liquid-vapor interface normal axis X (filled symbols), as well as that of the molecules constituting the first (dashed-dotted-dotted line), second (dashed line), and third (solid line) molecular layers beneath the interface, as obtained from the simulation at 298 K. The upper and lower insets show the comparison of this profile (filled circles) across the entire system, and in the surface molecular layer, respectively, with those obtained with the SPC/E (open circles) and TIP4P (open squares) water models. All profiles shown are averaged over the two interfaces present in the basic simulation box.
Average normal distance (i.e., distance along the macroscopic surface normal axis X) of two surface points as a function of their lateral distance l (i.e., distance in the YZ plane), as obtained in the first (left panel), second (middle panel), and third (right panel) molecular layer of water beneath its liquid-vapor interface at 298 K using the polarizable BK (filled circles), and the nonpolarizable the SPC/E (open circles), and TIP4P (open squares) water models.
Distribution of the induced (left curves) and total dipole moments (right curves) of the BK water molecules in the surface layer (solid curves), as well as in the second (dashed curves) and third (filled circles) molecular layers beneath the liquid-vapor interface at 298 K. The arrows indicate the values of the total dipole moment of the TIP4P and SPCE water models.
Cosine distribution of the angle formed by the permanent (solid curve), induced (dashed curve), and total dipole moment (filled circles) of the BK water molecules, as well as by the dipole moment of the SPC/E (open circles) and TIP4P (open squares) water models with the liquid-vapor interface normal axis pointing from the liquid to the vapor phase, X, in the surface molecular layer of the liquid phase at 298 K. The inset shows the cosine distribution of the angle between the permanent and induced dipole moments of the BK water molecules in the surface layer (solid curve) as well as in the second (dashed curve) and third (filled circles) molecular layers beneath the surface at 298 K.
(a) Definition of the local Cartesian frame fixed to the individual water molecules, and the polar angles ϑ and ϕ of the interface normal vector pointing from the liquid to the vapor phase, , in this frame. (b) Division of the surface molecular layer of water into regions A, B, and C (regions A and C corresponding mostly to the crests and troughs, respectively, of the molecularly rugged surface covering the liquid phase).
Orientational maps of the surface water molecules, as obtained at 298 K using the BK (top row), SPC/E (middle row), and TIP4P (bottom row) potential models in the entire surface layer (first column) as well as in its separate regions A (second column), B (third column), and C (fourth column). Lighter shades of grey correspond to higher probabilities. The preferred water orientations corresponding to the various peaks of the orientational maps are also illustrated. X is the macroscopic normal vector of the interface pointing from the liquid to the vapor phase.
Size distribution of the two-dimensional hydrogen bonded water clusters in the first (top panel), second (middle panel), and third (bottom panel) molecular layers of the liquid phase beneath the liquid/vapor interface, as obtained at 298 K with the BK (filled circles), SPC/E (open circles), and TIP4P (open squares) potential models. For better visibility, the data are shown on a logarithmic scale. The solid lines correspond to the critical line of Eq. (10) at the percolation threshold with the critical exponent for two-dimensional systems of α = 2.05.
Properties of the coexisting liquid and vapor phases of the BK water model. Estimated error of the last digits is given in parenthesis.
Critical parameters of various water models.
Properties of the first three subsurface molecular layers of liquid water, as obtained with the different models considered.
Article metrics loading...
Full text loading...