LayerPCM: An implicit scheme for dielectric screening from layered substrates

TL;DR

LayerPCM is a novel computational method combining polarizable continuum models with real-time density-functional theory to accurately simulate electrostatic interactions and ultrafast dynamics of molecules on multilayered dielectric substrates.

Contribution

It introduces LayerPCM, an efficient extension for modeling complex layered substrates and their effects on molecular electronic properties and dynamics.

Findings

Successfully models polarization effects on energy levels.

Simulates ultrafast laser-induced molecular dynamics.

Demonstrates robustness with realistic systems.

Abstract

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.