Water properties

Flexible SPC water model

The flexible simple point charge water model¹⁾ (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.²⁾

Properties³⁾	3-site model⁴⁾	Experiment
density, g/cm³	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

¹⁾ 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

²⁾ 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

³⁾ at standard conditions

⁴⁾ 5 ns simulation of 216 water molecules