Another implementation of sDFT with periodic boundary conditions based on the Quan-tumEspresso package was presented by Pavanello and coworkers . It uses a plane-wave basis throughout and features full Brillouin zone sampling while allowing for an arbitrary number of subsystems. To exploit the locality of the subsystems, smaller overlapping boxes are used to restrict the size of the plane wave basis for each subsystem. This is combined with a sophisticated parallelization scheme for a distributed treatment of the subsystems . Applications include molecular dynamics simulations of liquid water , also addressing its optical spectrum , and supercritical CO 2 . In addition, solid-solid and solid-liquid interfaces as well as surface-molecule interactions in complex condensed-phase systems have been studied (see below).