  Molecular dynamics simulations using classical force fields were carried out
to study energetic and structural properties of rotationally disordered clay
mineral-water-CO2 systems at pressure and temperature relevant to geological
carbon storage. The simulations show that turbostratic stacking of hydrated Na-
and Ca-montmorillonite and hydrated montmorillonite with intercalated carbon
dioxide is an energetically demanding process accompanied by an increase in the
interlayer spacing. On the other hand, rotational disordering of dry or nearly
dry smectite systems can be energetically favorable. The distributions of
interlayer species are calculated as a function of the rotational angle between
adjacent clay layers.
