Ab Initio Ice, Dry Ice, and Liquid Water

This chapter summarizes the recent applications of ab initio wave function theory (WFT) to a variety of properties of water ices, liquid water, and solid CO2 as well as the embedded fragmentation techniques that enable such applications at ab initio theory levels of second-order MP (MP2) and coupled-cluster with singles and doubles (CCSD). They mark the beginning of a new era of condensed matter simulations based on systematic ab initio WFT. The chapter also reviews the embedded-fragment methodology taking an application to a solid as an example. It has enabled ab initio calculations of a wide variety of properties of molecular crystals, amorphous solids, and liquids at finite temperature and pressure. Finally, the chapter addresses the different thermodynamic conditions (temperature and pressure) required to keep ''MP2-water'' in the liquid phase from the ambient conditions.