There are positive partial charges on the two hydrogens and the negative partial charge of oxygen lies on the angle bisector of the HOH angle. The partial charges sum to zero to make the molecule electrostatically neutral. The OH bonds are symmetric in length and the entire molecule is rigid, i. e. all vibrational degrees of freedom are frozen. The total potential energy comprises of a Lennard-Jones potential and electrostatic potential contributions as there are no bonded interactions. The short range interaction is modeled by a 12-6 Lennard-Jones potential and the long range dispersion beyond the cutoff is analytically estimated as a homogeneous solution for only for the attractive portion of the Lennard-Jones potential since the dispersion correction for the repulsive part is negligibly small. The electrostatic potential is modeled using Coulomb potential. In the simulations, the long-range Coulomb contribution is estimated using a Particle Mesh Ewald sum as implemented in GROMACS.