## Regional embedding of many-electron correlation methods

In this research field we work on computational embedding techniques, which allow to apply accurate quantum chemical many-electron theories to regional quantum phenomena in periodic environments, such as molecule-surface interactions or defects in solids.

In Reference [1] we present an algorithm that reaches rapid convergence of the coupled cluster correlation energy with respect to the embedded fragment size. A special feature is the rigorous inclusion of the long-range van der Waals correlation between the embedded fragment and its environment, which is achieved by a seamless integration of coupled cluster theory into the random phase approximation (RPA) using a plane-wave basis set.

[1] Schaefer et al., J. Chem. Phys. 154, 011101 (2021), “Local embedding of coupled cluster theory into the random phase approximation using plane waves”

Figure: visualization of a possible local density partition of a water molecule on titanium oxide.