--- trunk/iceiPaper/iceiPaper.tex 2005/01/06 20:04:03 1905 +++ trunk/iceiPaper/iceiPaper.tex 2005/01/06 21:00:26 1906 @@ -388,20 +388,31 @@ So what is the preferred solid polymorph for simulated conditions, such as the density in fixed-volume simulations, can influence the polymorph expressed upon crystallization. -So what is the preferred solid polymorph for simulated water? The -answer appears to be dependent both on the conditions and the model -used. In the case of short cutoffs without a long-range interaction -correction, Ice-{\it i} and Ice-{\it i}$^\prime$ have the lowest free -energy of the studied polymorphs with all the models. Ideally, -crystallization of each model under constant pressure conditions, as -was done with SSD/E, would aid in the identification of their -respective preferred structures. This work, however, helps illustrate -how studies involving one specific model can lead to insight about -important behavior of others. In general, the above results support -the finding that the Ice-{\it i} polymorph is a stable crystal -structure that should be considered when studying the phase behavior -of water models. +\section{Conclusions} +In this report, thermodynamic integration was used to determine the +absolute free energies of several ice polymorphs. Of the studied +crystal forms, Ice-{\it i} was observed to be the stable crystalline +state for {\it all} the water models when using a 9.0 \AA\ +intermolecular interaction cutoff. Through investigation of possible +interaction truncation methods, the free energy was shown to be +partially dependent on simulation conditions; however, Ice-{\it i} was +still observered to be a stable polymorph of the studied water models. + +So what is the preferred solid polymorph for simulated water? As +indicated above, the answer appears to be dependent both on the +conditions and the model used. In the case of short cutoffs without a +long-range interaction correction, Ice-{\it i} and Ice-{\it +i}$^\prime$ have the lowest free energy of the studied polymorphs with +all the models. Ideally, crystallization of each model under constant +pressure conditions, as was done with SSD/E, would aid in the +identification of their respective preferred structures. This work, +however, helps illustrate how studies involving one specific model can +lead to insight about important behavior of others. In general, the +above results support the finding that the Ice-{\it i} polymorph is a +stable crystal structure that should be considered when studying the +phase behavior of water models. + We also note that none of the water models used in this study are polarizable or flexible models. It is entirely possible that the polarizability of real water makes Ice-{\it i} substantially less