Molecular orbital theory for infinite molecular aggregates: Application to idealized hexagonal and cubic ices

A single determinant molecular orbital theory for infinite molecular aggregates is developed. Calculations based on this theory are reported for idealized hexagonal and cubic ice structures in which the protons are ordered. The hexagonal structure is found to be the more stable by 0.75 kcal/mole. This stabilization is attributed in part to favourable three molecule interactions in the hexagonal lattice. The bond angles for the two independent …