Molecular Association in Liquids. II. A Theory of the Structure of Water

Previous theories of the structure of liquid water have either placed undue emphasis on crystalline structures or have postulated that too many hydrogen bonds connecting neighbouring molecules are broken. In this paper a theory is developed in which the majority of hydrogen bonds are regarded as distorted rather than as broken. The structural changes are examined quantitatively with the aid of a simple expression for the energy of a bent hydrogen bond. It is shown that the use of a bending force constant consistent with electrostatic calculations on simple models of water molecules leads to a satisfactory quantitative explanation of the observed radial distribution function, the discontinuity in density associated with the melting of ice, and the observed values of the dielectric constant of water.