Importance of electrostatic interactions between nonbonded molecules in ice

Abstract

Ab initio calculations on water dimer, trimer, Pm11 polymer, I41md prototype structure, and ice VIII shows that the dependence of the O-H bond length upon the intermolecular distance mostly depends upon environmental effects due to non-H-bonded molecules. The hydrogen bonds are found to be weaker in ice VIII and Pm11 polymer than in the I$4_1$md structure. This result is consistent with recent experiments on He-${\mathrm{H}}_2$O and ${\mathrm{H}}_{2\mathrm{-}}$ ${\mathrm{H}}_2$O clathrates and emphasizes the role of interactions between nonbonded molecules. These effects can be qualitatively understood by a simple dipole-dipole electrostatic model.