  We present LayerPCM, an extension of the polarizable-continuum model coupled
to real-time time-dependent density-functional theory for an efficient and
accurate description of the electrostatic interactions between molecules and
multilayered dielectric substrates on which they are physisorbed. The former
are modelled quantum-mechanically, while the latter are treated as polarizable
continua characterized by their dielectric constants. The proposed approach is
purposely designed to simulate complex hybrid heterostructures, with
nano-engineered substrates including a stack of anisotropic layers. LayerPCM is
suitable to describe the polarization-induced renormalization of frontier
energy levels of the adsorbates in the static regime. Moreover, it can be
reliably applied to simulating laser-induced ultrafast dynamics of the
molecules through the inclusion of electric fields generated by
Fresnel-reflection at the substrate. Depending on the complexity of the
underlying layer structure, such reflected fields can assume non-trivial shapes
and profoundly affect the dynamics of the photo-excited charge carriers in the
molecule. In particular, the interaction with the substrate can give rise to
strong delayed fields which lead to interference effects resembling those of
multi-pulse-based spectroscopy. The robustness of the implementation and the
above-mentioned features are demonstrated with a number of examples, ranging
from intuitive models to realistic systems.
