A cooperative calculation and analysis of electric fields, induced dipole vectors and lattice energies for rotationally ordered ices IX, II and disordered Ih of Different Ice Forms Abstract: A non-additive model previously tested on 229 Hartree-Fock dimer energies an do trimer energies has been supplemented with different dispersion contributions and used to calculate the following properties of rotationally ordered ices IX and II and of disordered Ih: (a) the different contributions to the lattice energy; (b) the induced dipole vectors, electric fields and angle relations as a function of lattice site and of molecular orientation for Ih. The calculated results are discussed in terms of an interpretation of the preferred relative orientations of water molecules. The non-cooperative contribution for this model was found to be enhanced in a range from 50 to 100 per cent over that of trimer interactions.