TIP4P model

The hydration dynamics were also studied by Karim et al. [58], These authors used the TIP4P model of water in their molecular dynamics simulations. The observed hydration dynamics was nonexponential with average time constant in the range of 0.4-0.7ps. In this case simulated relaxation of the first solvation shell was also faster than that of the other shells. 

M.J. Vlot et al., Free energy calculations on systems of rigid molecules An application to the TIP4P model of H20. J. Chem. Phys. 110, 55-61 (1999)... 

Figure 3 Above Radial distribution functions for water samples at 25 C using the TIP4P potential (solid line) and the TIP4P potential plus a localized repulsive barrier (dashed line), as discussed in the text. Below Constant potential surfaces of the localized repulsion added to the TIP4P model. The surfaces correspond to an energy value of 1 kT.

This is confirmed by a recent comparison [90] of calculated and experimental values of second virial coefficient in the temperature range 298-373 K, which turned out underestimated by as much as 300 % by the TIP4P model. 

Among collective dynamical properties, some turn out more sensitive than others to potential models. It can be noticed from Table 4 that, e.g., dielectric relaxation times Tq and thermal conductivity, A, coefficient agree satisfactorily with experiments both at 300 and 255 K, while shear viscosity, r], is largely underestimated, especially in the supercooled region. Longitudinal viscosity, is also underestimated, but to a lesser extent. We recall that the defect of a too fast dynamics, compared with supercooled real water, is shared by the TIP4P model [164]. 

TIP4Pfd model [121]. Thus, from this point of view TIP4Pfd does not significantly improve over the original effective TIP4P model. However, the limited size of the sample considered, that included only monovalent alkaline cations (Li", Na", K" ) and anions (F, Cl", Br") prevents us from drawing definite conclusions. 

Jorgensen et al [188] tend to reduce the importance of these effects, noting that Perera et al actually used a TIP4P model with modified charges and that the original TIP4P model was able to predict surface-type structure for clusters of Cl with 14 water molecules. 

The variations of the charges and Lennard-Jones parameters for the reacting system are also expressed as smooth functions of r. We prefer to describe the solvent-solvent interactions by the well-proven TIP4P model for water ° and by the OPLS potentials for organic liquids. ... 

It is increasingly realized that many-body induction interactions should be included in computer models, especially in inhomogeneous environments. Kohlmeyer et al. [44] therefore investigated the role of molecular polarizability on the density profiles of a slab of water in contact with several different metal surfaces. They employed the polarizable TIP4P model by Rick and Berne [46]. It was found that the density profiles are almost identical near a metallic surface the liquid/gas interface appears to become slightly wider. Earlier studies of polarizable water at a hydro-phobic wall by Wallqvist [141] and near the liquid/gas interface by Motakabbir and Berkowitz [142] also concluded that polarization effects are of secondary importance. 

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