Department of Chemistry and Biochemistry
University of Notre Dame
Notre Dame, Indiana 46556

The absolute free energies of several ice polymorphs were calculated using thermodynamic integration. These polymorphs are predicted by computer simulations using a variety of common water models to be stable at low pressures. A recently discovered ice polymorph that has as yet only been observed in computer simulations (Ice-i), was determined to be the stable crystalline state for all the water models investigated. Phase diagrams were generated, and phase coexistence lines were determined for all of the known low-pressure ice structures. Additionally, potential truncation was shown to play a role in the resulting shape of the free energy landscape.