Density and porosity of amorphous water ice by DFT methods

Abstract A theoretical method is developed to study amorphous ices, based on solid state calculations at DFT level. The method is applied to amorphous water ice of a large range of densities, between 0.6 g cm−3 and 1.6 g cm−3 to represent low-density and high-density amorphous ices, at 40 K and 140 K. The most stable forms appear for densities in good agreement with experimental data, ρ ~ 0.9–1.0 g cm−3 and ρ ~ 1.1–1.2 g cm−3. The method allows evaluating the porosity through the intrinsic density, providing a possible way to estimate the porosity of astrophysical ices.