Totally ab Initio Prediction of the Structures of CO₂ Molecular Crystal

T. Hirano, S. Tsuzuki, K. Tanabe, and N. Tajima
[Chem. Lett., No.12, pp.1073-1074, 1995]

We have succeeded in predicting a molecular crystal structure from first principles. The potential parameters and geometry for CO₂ molecule were determined by ab initio molecular orbital calculations. The experimentally observed CO₂ crystal structures at low and high pressures have been reproduced by molecular dynamics method without any a priori assumptions on lattice constants nor space group symmetry. With extra pressure of 1 GPa in [010] direction, the structural change observed at about 10 GPa has also been reproduced.

Table 1. Gibbs free energie at 100 K and lattice constants of CO₂ crystal structures predicted by our ab initio potentials