The dipolar correlation factor, the electrostatic field, the dipole moment, and the Coulombic interaction energy of water molecules in clathrate hydrates

The dipolar correlation factor g, the electrostatic field E, the dipole moment μ, and the Coulombic interaction energy U of water molecules in clathrate hydrates of structure I and structure II have been calculated from the molecular data for their crystal structures in space groups Pm3n and Fd3m, respectively. For dendritic probabilities of orientation of water molecules in fully proton-disordered structures, the values of g are 2.876 and 2.899, of E are 0.2861 and 0.262 Mesu cm−2, of μ are 2.4133 and 2.4135 D, and of U are −7.99 and −7.93 kJ/mole H bond. The dipole moment of H2O is increased by nearly 30% over its vapor phase value. The dielectric permittivity of the two clathrate hydrates calculated from the above values of g and μ are significantly higher than those measured. The values of g, μ, E, and U are somewhat lower than in ice Ih and Ic. The results are discussed in terms of the lack of complete disorder of proton positions in the two structures of clathrate hydrates.