Dynamical Downfolding of Interacting Quasiparticles in Chemical Interfaces

The Dynamical Downfolding approach constructs a static effective Hamiltonian by mapping a large problem on a set of interacting quasiparticles, requiring one to solve a set of auxiliary frequency-dependent one- and two-body propagators. This static Hamiltonian that can be efficiently tackled with highly correlated methods. In this work, we apply dynamical downfolding to explore interactions in a realistic system consisting of a molecule (subspace of interest) on a surface in combination with the Density Matrix Renormalization Group (DMRG) solver to obtain many-body ground and excited states. We examine how the choice of downfolding subspace in the DMRG calculation affects the molecule's excitation spectra, and how sampling surface states in the correlated subspace can be used to capture the renormalization of molecular states by the surface.