Excited-State Downfolding Using Ground-State Formalisms
Abstract
Downfolding coupled cluster (CC) techniques are powerful tools for reducing the dimensionality of many-body quantum problems. This work investigates how ground-state downfolding formalisms can target excited states using non-Aufbau reference determinants, paving the way for applications of quantum computing in excited-state chemistry. This study focuses on doubly excited states for which canonical equation-of-motion CC approaches struggle to describe unless one includes higher-than-double excitations. The downfolding technique results in state-specific effective Hamiltonians that, when diagonalized in their respective active spaces, provide ground- and excited-state total energies (and therefore excitation energies) comparable to high-level CC methods. The performance of this procedure is examined with doubly excited states of H, Methylene, Formaldehyde, and Nitroxyl.
Cite
@article{arxiv.2310.13752,
title = {Excited-State Downfolding Using Ground-State Formalisms},
author = {Nicholas P. Bauman},
journal= {arXiv preprint arXiv:2310.13752},
year = {2023}
}