neglected in that study, later work investigated these effects in terms of an embedded many-body expansion . Vertical excitation energies for rhodopsin and three different visual cone pigments have also been calculated in Ref. 215 using NAKE-based CC2-in-DFT embedding. The models employed included part of the protein binding pockets, resulting in models with about 330 to 370 atoms in total. For enhanced efficiency, the authors presented an implementation of Laplace-transform scaled-opposite-spin CC2 version making use of the resolution-of-the-identity approximation.