Electronic Structure for Multielectronic Molecules Near a Metal Surface

TL;DR

This paper presents a model for multi-electronic molecules on metal surfaces, demonstrating accurate ground state wavefunctions and excitation energies using a reduced Hamiltonian, aiding future studies of surface charge transfer and reactions.

Contribution

It introduces a reduced configuration interaction Hamiltonian that accurately captures ground and excited states of multi-electronic molecules near metal surfaces, even with weak coupling.

Findings

Accurate ground state wavefunctions comparable to NRG results.

Extraction of meaningful excitation energies.

Applicable to weak metal-molecule coupling regimes.

Abstract

We analyze a model problem representing a multi-electronic molecule sitting on a metal surface. Working with a reduced configuration interaction Hamiltonian, we show that one can extract very accurate ground state wavefunctions as compared with the numerical renormalization group theory (NRG) -- even in the limit of weak metal-molecule coupling strength but strong intramolecular electron-electron repulsion. Moreover, we extract what appear to be meaningful excitation energies as well. Our findings should lay the groundwork for future {\em ab initio} studies of charge transfer processes and bond making/breaking processes on metal surfaces.