# Difference between revisions of "TIP4P model of water"

The TIP4P model [1] is a rigid planar four-site interaction potential for water, having a similar geometry to the Bernal and Fowler model, which was proposed in 1933.

## Parameters

The TIP4P model consists of a Lennard-Jones site for the oxygen atom, and three charge sites.

 $r_{\mathrm {OH}}$ (Å) $\angle$HOH , deg $\sigma$ (Å) $\epsilon/k$ (K) q(O) (e) q(H) (e) q(M) (e) $r_{\mathrm {OM}}$ (Å) 0.9572 104.52 3.154 78.0 0 0.52 -2q(H) 0.15

## Phase diagram

The following is the phase diagram of the TIP4P model in the pressure-temperature plane (adapted from Fig. 11 of [2]).

### Plastic crystal phases

Recent simulations have demonstrated the existence of plastic crystal phases for the TIP4P model [2].

### Melting point

The melting point ice Ih-water at 1 bar is $232(4)~K$[3].

## Shear viscosity

The shear viscosity for the TIP4P model is 0.494 mPa.s at 298 K and 1 bar [4] (experimental value 0.896 mPa.s [5]).

## Virial coefficients

The second virial coefficient has been calculated by Chialvo et al [6].