====== Water properties ======
{{:water-1728.png?400}}

===== Flexible SPC water model =====


The **flexible simple point charge water model**((K. Toukan and A. Rahman (1985). "Molecular-dynamics study of atomic motions in water". //Physical Review B// v.31 pp.2643–2648. DOI:10.1103/PhysRevB.31.2643)) (or Flexible SPC water model) is a re-parametrization of the three-site SPC water model. The SPC model is rigid, whilst the flexible SPC model is elastic with anharmonic O-H stretching. This is one of the most accurate three-center water models without taking into account the polarization. In molecular dynamics simulations it gives the correct density and dielectric permittivity of water.((M. Praprotnik, D. Janezic and J. Mavri (2004). "Temperature Dependence of Water Vibrational Spectrum: A Molecular Dynamics Simulation Study". //Journal of Physical Chemistry A// v.108 pp.11056–11062))

^ Properties((at standard conditions)) ^ 3-site model((5 ns simulation of 216 water molecules)) ^ Experiment       ^
| density, g/cm<sup>3</sup>                | 1.002     | 0.99716 | 
| temperature of maximum density (TMD), ºC | -22        | +4    |
| heat of vaporization, kcal/mol           | -11.53     | -10.5 |
| dielectric permittivity                  | 91         | 78    |
| diffusion coefficient                    | 2.4        | 2.3   |