Pressure-Induced Solid Carbonates from Molecular CO 2 by Computer Simulation

Abstract

A combination of ab initio molecular dynamic simulations and fully relaxed total energy calculations is used to predict that molecular CO₂ should transform to nonmolecular carbonate phases based on CO₄ tetrahedra at pressures in the range of 35 to 60 gigapascals. The simulation suggests a variety of competing phases, with a more facile transformation of the molecular phase at high temperatures. Thermodynamically, the most stable carbonate phase at high pressure is predicted to be isostructural to SiO₂α-quartz (low quartz). A class of carbonates, involving special arrangements of CO₄ tetrahedra, is found to be more stable than all the other silica-like polymorphs.